Katy Perry

trounced Lady Gaga in this week’s showdown of the pop female megastars. Perry’s “Roar” sold 557K copies in its first week on sale, about 2-1/2 times as many as Gaga’s “Applause” (218K). The total for “Roar” is the third-highest first-week sales tally in digital history. It trails Flo Rida’s “Right Round” (636K in February 2009) and Taylor Swift’s “We Are Never Ever Getting Back Together” (623K in August 2012).

This is the biggest one-week sales tally of Perry’s career. It tops her anthemic “Firework,” which sold 509K copies in its 11th week in December 2010.

“Roar” vaults from #85 to #2 in its second week on the Hot 100 (it debuted last week based just on airplay points). It was blocked from the top spot by “Blurred Lines” by Robin Thicke featuring T.I. + Pharrell, which holds at #1 for the 11th week. (The Hot 100 measures not only digital sales, but also radio airplay and streaming activity.)

“Blurred Lines” becomes the longest-running #1 hit since the Black Eyed Peas’ “I Gotta Feeling” topped the chart for 14 weeks in 2009. It’s the longest-running #1 by a male artist or an all-male collabo since “Yeah!” by Usher featuring Lil Jon & Ludacris logged 12 weeks on top in 2004. (I’ll have more on “Blurred Lines” in a minute.)

“Applause” enters the Hot 100 at #6. It’s Gaga’s fifth single to debut in the top 10, though it fell short of the debut positions of two of her previous hits. “Born This Way” opened at #1. “The Edge Of Glory” bowed at #3.

These are the 12th top 10 hits for both Perry and Gaga. Perry had a nearly six-month head-start in piling up top 10 hits. She first cracked the top 10 with “I Kissed A Girl” in June 2008. Gaga first cracked the top 10 with “Just Dance” featuring Colby O’Donis that December. These are the first singles from the superstars’ upcoming third albums. Perry’s Prism is due Oct. 22. Gaga’s ARTPOP is due Nov. 11.

It will be interesting to see if Perry’s hit makes it to #1. A boffo first-week sales number doesn’t guarantee a #1 ranking. Just ask Justin Bieber, whose “Boyfriend” sold 521K in its first week; Maroon 5 featuring Wiz Khalifa, whose “Payphone” sold 493K in its first week; or Taylor Swift, whose “I Knew You Were Trouble.” sold 416K in its first week. All three songs peaked at #2. Reaching #1 often comes down to timing and plain luck.

Many have noted similarities between “Roar” and Sara Bareilles’ “Brave.” The comparisons have drawn attention to “Brave.” The song jumps from #66 to #46 in its 10th week, surpassing its initial peak at #61. The song sold 51K digital copies this week, up 80% from 28K last week.

(You do get the sense that Perry is steeped in pop history. Her hit echoes lyrics from two former #1 hits: Helen Reddy’s “I Am Woman” (“hear me roar”) and Survivor’s “Eye Of The Tiger,” as well as Queen’s top five hit “We Are The Champions.”)

“Blurred Lines” is also #1 on Hot R&B/Hip-Hop Songs for the 11th week. This equals the mark set by Thicke’s 2007 hit “Lost Without U.” But of course “Blurred Lines” is a vastly bigger crossover hit. “Lost Without U” peaked at #14 on the Hot 100.

For the third week in a row, “Blurred Lines” set a new record for the most “all-format audience impressions” since Nielsen BDS starting measuring such things in 1990. The song had 228.9 million impressions this week.

This marks the first time that a song titled “Applause” has made the Hot 100, though a different song with that title made a splash in pop culture in 1970. Bonnie Franklin (who went on to TV fame in One Day At A Time) sang “Applause” in the hit Broadway musical of the same name. The great Pearl Bailey covered the song and took it to #37 on the Easy Listening chart (as it was called then). (OK, I’m a nerd.)

“Applause” zooms from #16 to #1 on the Dance/Electronic Songs chart, displacing “Get Lucky” by Daft Punk featuring Pharrell Williams.

“Applause” enters the U.K.’s Official Singles Chart at #5. Gaga got more good news from the U.K. this week. “Bad Romance” became her second million-seller in the U.K., following “Poker Face.” Gaga is the first American-born female artist ever to land two million-selling singles in the U.K. She’s just the fourth female artist overall to achieve the feat. Rihanna (who was born in Barbados) is out front with three U.K. million-sellers. Olivia Newton-John (born in England) and Celine Dion (born in Canada) have each notched two.

In the U.S., Gaga is the only artist with two songs in the top 10 on Nielsen SoundScan’s running list of the 200 best-selling songs in digital history. “Poker Face” ranks #6. “Just Dance” ranks #8. The Black Eyed Peas had two of the all-time top 10 digital hits from December 2009 through June 2013, but “Boom Boom Pow” was nudged out at the end of June (by “Thrift Shop”).

Miley Cyrus’

“We Can’t Stop” dips from #2 (where it spent three non-consecutive weeks) to #3. This is its ninth week in the top 10. Among Cyrus’ hits, only “Party In The U.S.A.” has had as many or more weeks in the top 10. It held tight for 16 weeks in 2009. “We Can’t Stop” is #1 on the Streaming Songs chart for the ninth week.

Imagine Dragons’ “Radioactive” dips from #3 (where it spent four non-consecutive weeks) to #4. This is its 10th consecutive week in the top five. The song is #1 on Rock Songs for a record-extending 22nd week.

“Holy Grail” by Jay Z featuring Justin Timberlake holds at #5 for the third week. The song tops the 1 million mark in digital sales this week.

Anna Kendricks’

“Cups (Pitch Perfect’s When It’s Gone)” drops from #6 to #8. This is its sixth week in the top 10. “Six” is the magic number for this project. The Pitch Perfect soundtrack spent six weeks in the top 10 on The Billboard 200. And the movie itself spent six weeks in the top 10 on the box-office chart.

Here's the low-down on this week's top 10 songs.

The Top Five: “Blurred Lines” by Robin Thicke featuring T.I. + Pharrell holds at #1 for the 11th week in its 18th week on the chart. This is its 12th week in the top 10. Digital sales rank: #2 (291K)…Katy Perry’s “Roar” vaults from #85 to #2 in its second week. It’s her 12th top 10 hit. Digital sales rank: #1 (557K)…Miley Cyrus’ “We Can’t Stop” dips from #2 to #3 in its 11th week on the chart. This is its ninth week in the top 10. Digital sales rank: #6 (148K)…Imagine Dragons’ “Radioactive” dips from #3 to #4 in its 51st week on the chart. This is its 18th week in the top 10. Digital sales rank: #8 (121K)…“Holy Grail” by Jay Z featuring Justin Timberlake holds at #5 for the third week in its sixth week on the chart. It has been in the top 10 the entire time. Digital sales rank: #4 (178K).

The Second Five: Lady Gaga’s “Applause” debuts at #6. It’s her 12th top 10 hit. Digital sales rank: #3 (218K)… “Get Lucky” by Daft Punk featuring Pharrell Williams drops from #4 to #7 18th week on the chart. This is its 14th week in the top 10. Digital sales rank: #17 (79K)… Bruno Mars’ “Treasure” dips from #7 to #8 in its 14th week on the chart. This is its ninth week in the top 10. Digital sales rank: #11 (91K)…Anna Kendrick’s “Cups (Pitch Perfect’s When I’m Gone)” drops from #6 to #9 in its 34rd week on the chart. This is its seventh week in the top 10. Digital sales rank: #13 (91K)…Capital Cities’ “Safe And Sound” dips from #9 to #10 in its 16th week on the chart. This is its third week in the top 10. Digital sales rank: #14 (88K).

Two songs drop out of the top 10 this week. “Clarity” by Zedd featuring Foxes drops from #8 to #12. Maroon 5’s “Love Somebody” drops from #10 to #13.

Avicii’s

“Wake Me Up!” jumps from #15 to #11 in its eighth week. Digital sales rank: #7 (138K). The song spent three weeks at #1 on the U.K.’s Official Singles Chart.

“Summertime Sadness” by Lana Del Rey & Cedric Gervais jumps from #16 to #15 in its sixth week. It's likely to become Del Rey's first top 10 hit. Digital sales rank: #9 (117K).

Luke Bryan’s

“That’s My Kind Of Night” is the week’s second-highest new entry at #16. Digital sales rank: #5 (164K). The song is from Bryan’s Crash My Party, which enters The Billboard 200 with sales of 528K. By reaching #16, the song ties “Drunk On You” from 2012 as Bryan’s highest-charting hit to date on the Hot 100. Also, it vaults from #35 to #1 on Hot Country Songs, bumping Florida Georgia Line’s “Cruise” out of the top spot after a record-setting 24-week run on top. It’s Bryan’s fifth #1 country hit.

Bryan’s previous single, “Crash My Party,” jumps from #27 to #22 in its 19th week. The song has climbed as high as #18. The song’s sales this week were held back because many fans who had previously purchased the song opted to take advantage of iTunes’ “Complete My Album” feature. Those transactions, when fans “trade up” and buy the digital album, are deducted from the song’s sales for the week.

“Cruise” has sold 5,638,000 copies. This week, it moves up to second place on Nielsen SoundScan’s running list of the best-selling country songs in its history. Lady Antebellum’s “Need You Now” is #1 (6,198,000). Taylor Swift’s “Love Story” dips to third place (5,609,000). “Cruise” also becomes the fourth song to sell 4 million copies in 2013. (On the Hot 100, the song, credited to Florida Georgia Line featuring Nelly, drops from #14 to #19 in its 46th week.)

Lorde’s “Royals” jumps from #24 to #17 in its seventh week. Digital sales rank: #10 (107K).

“Just Give Me A Reason” by P!nk featuring Nate Ruess, which drops from #22 to #28 in its 27th week, tops the 4 million mark in digital sales. It’s the third biggest seller for both acts. For P!nk, it trails “So What” (4,624,000) and “Raise Your Glass” (4,162,000). For Ruess, it trails fun.’s “We Are Young” (featuring Janelle Monae, 6,735,000) and “Some Nights” (4,826,000). (P!nk’s follow-up, “True Love” (featuring Lily Allen), jumps from #69 to #60 in its third week.)

Selena Gomez’s “Come & Get It,” which drops from #23 to #31 in its 19th week, tops the 2 million mark in digital sales. It’s her second song to reach this level, following “Love You Like A Love Song” (which she recorded with The Scene, 2,502,000).

Keith Urban

lands his 15th top 40 hit on the Hot 100 as “Little Bit Of Everything” jumps from #43 to #33 in its 13th week. It’s already Urban’s highest-charting hit since “Kiss A Girl” reached #16 in June 2009, which suggests that his exposure on American Idol did him some good. He’s good on the show. He’ll be back next season…Carrie Underwood’s “See You Again” jumps from #41 to #34 in its 16th week. This is the second time in a little more than five years that a song with that title has been a hit. Miley Cyrus took a song with the same title to #10 in May 2008…Thomas Rhett’s “It Goes Like This” jumps from #49 to #40 in its 10th week…Paramore’s “Still Into You” jumps from #57 to #45 in its sixth week.

“Beware” by Big Sean featuring Lil Wayne & Jhene Aiko jumps from #79 to #59 in its fourth week…Tim McGraw’s “Southern Girl” jumps from #72 to #64 in its fourth week…Blake Shelton’s “Mine Would Be You” jumps from #75 to #65 in its third week… “Love More” by Chris Brown featuring Nicki Minaj jumps from #90 to #73 in its fourth week. The song has climbed as high as #56…Passenger’s “Let Her Go” jumps from #86 to #74 in its third week…Sheryl Crow’s “Easy” jumps from #97 to #84 in its fourth week…Taylor Swift’s “Red” jumps from #100 to #85 in its seventh week. The song has climbed as high as #6.

Panic! At The Disco’s

“This Is Gospel” debuts at #87. It’s from the group’s fourth studio album, Too Weird To Live, Too Rare To Die!, which is due Oct. 8…The Wanted’s “We Own The Night” debuts at #94...Bastille’s “Pompeii” debuts at #95. It’s from the British band’s first U.K. album, Bad Blood. This song reached #2 on the U.K.’s Official Singles Chart… Little Big Town’s “Your Side Of The Bed” debuts at #96. It’s from the group’s fifth album, Tornado, which reached #2 in September 2012…“Bruises” by Train featuring Ashley Monroe debuts at #97. It’s from the group’s sixth studio album, California 37, which was released in April 2012.

John Mayer’s

“Wildfire” re-enters the chart at #98. The song has climbed as high as #91. It’s from Mayer’s sixth studio album, Paradise Valley, which is expected to challenge Luke Bryan’s album for #1 next week… “Without Me” by Fantasia featuring Kelly Rowland and Missy Elliott re-enters the chart at #100. The song has climbed as high as #74.

Ellie Goulding’s “Burn” debuts at #1 on the U.K.s Official Singles Chart. It’s her first #1 in her home country. Her version of Elton John’s “Your Song” reached #2 in 2010. “Burn” has climbed as high as #53 on the Hot 100.

M.I.A.’s “Paper Planes” tops the 4 million mark in digital sales this week. The smash reached #4 on the Hot 100 in September 2008. It received a Grammy nomination for Record of the Year.