"My mom broke her arm," Sailor explained in her pre-taped interview package. "She asked me if I wanted to fill in for her."
"I have never danced before," she continued. "But I feel this adrenaline rush for wanting to pay homage to my mom. My mom's had three weeks to prepare this dance, and now I have three days. This is for you, Mom."
Despite only having three days to train and learn the routine, Sailor slayed her Foxtrot to "Uptown Girl," wowing the audience and judges with her fancy footwork and infectious smile. Christie was in the audience, proudly cheering on her daughter.
"I am blown away," raved judge Carrie Ann Inaba, as Bruno Tonioli agreed, saying, "Trust my word ... I can't wait to see what you achieve with proper rehearsal time."
"I am so proud of her," Christie gushed as she joined Sailor and Val onstage. Sailor and Val received a total of 18/30 from the judges.
Earlier on Monday, just a few hours ahead of the premiere, ABC announced that the actress would no longer be competing after suffering injuries during rehearsals.
"While rehearsing for the premiere of Dancing With the Stars, Christie Brinkley suffered injuries which required surgery to her wrist and arm," ABC shared in a statement. "She is unable to continue her planned participation on the show. Keeping it all in the family, her daughter, Sailor Brinkley-Cook, a Sports Illustrated model, has chosen to quickly step in with hours to learn the entire routine and will compete in her mother’s place for the remainder of the season. We wish Christie a full and speedy recovery and look forward to seeing her in the audience, whenever possible, proudly supporting Sailor."
Christie took to her own Instagram shortly after the announcement was made to provide even more details on her abrupt exit.
"Sailor Breezes In to Save the Day!" she captioned a pic of her daughter in costume. "I just broke my arm into a 1000 pieces requiring surgery with a metal plate and screws to hold my arm together..I'm so sorry if I've disappointed anybody! Only something as bad as this could stop me from continuing to dance with my wonderful coach...I was having a blast!"
"Shattering my arm was quite literally a crushing disappointment," she continued. "I never ever want to let anyone down, so I looked for a silver lining and i think this one is solid gold! Sailor!"
Sailor shared her mom's post to her Instagram Stories, writing, "Surprise!!! This has been a whirlwind of emotions but all I can say is wish me good luck."
The sparkly blue costume Sailor was wearing in her first promo pic for the show appears to be the same one Christie tried on just 24 hours before premiere night:
Last month, ET spoke to Brinkley following the season 28 cast reveal, where she joked about how inexperienced she was.
"I literally don't know how to dance. Seriously, it's true… I really don't have the moves," she said at the time. "So I'm really excited to learn with the pros. It's a wonderful opportunity for me."
"I think whoever I get has his work cut out for him," she continued. "I think they need to give me a really good one because I need a lot of work… All of the dancers on the show are incredible, really amazing."
Hear more in the video below.