Serena Williams Post Photo of 'Ab Muscle' Work Out After Baby No. 2: 'Here Comes Fitness!'

The tennis icon welcomed her second daughter, Adira River, in August

Serena Williams’ eldest daughter is her number one supporter!

On Saturday, the tennis ace, 42, shared a photo on Instagram that showed her working on her ab muscles in the gym. In the snap, Williams was joined by her 6-year-old daughter Olympia, who kept a watchful eye on her.

“Olympia watching me try to get my ab muscles working again. Here comes fitness!” the seven-time Wimbledon champion — who welcomed second daughter Adira River in August with her husband Alexis Ohanian — wrote in her caption.

In the photo, Williams laid on her back with her hands on her lower stomach on an exercise mat. Her head was blocked from view by Olympia, who sat cross-legged at the top of the mat watching her mom as she trained.

Related: Serena Williams Shares New Photos Cozying Up with Daughters Adira and Olympia

The athlete shares her two daughters with Ohanian, 40, and the entrepreneur was quick to share his delight at the snap.

“Love this photo,” he wrote in the comment section.

Williams and her husband first announced the arrival of their daughter Adira on TikTok on Aug. 22. Ohanian then shared the name of their baby girl in an Instagram post the same day.

"Welcome, Adira River Ohanian," the dad of two captioned a family photo at the time, which revealed Adira's name. "I'm grateful to report our house is teaming [sic] with love: a happy & healthy newborn girl and happy & healthy mama. Feeling grateful."

Related: Serena Williams Shares Huge Haul of Nike Clothes Gifted to Her for Baby Adira: 'Always So Sweet'

Williams’ workout photo with her eldest daughter came just days after she gave fans a glimpse of her new baby girl Adira in new photos shared on her Instagram Story.

In the first post, Williams shared a photo of the little one sporting a pair of white socks as she laid on a fluffy blanket, while eldest daughter Olympia made an appearance in the following picture.

In the second snap, Williams sat with Adira resting on her chest, wearing a moon-print sleepsuit. A sleepy-looking Olympia sat beside the pair with her head resting on a cushion.

In September, Williams shared in a video the gifts her baby daughter had received from Nike, who she has long partnered with.

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"Look at all this stuff for baby Adira," Williams said in her Instagram Story at the time, as she showcased a chest of Nike baby clothes and a pair of cute shoes in the clip.

"I really love the little Nike shoes, just always so sweet," the mom of two gushed. "Look at this little crop top!"

"It's pretty awesome," Williams concluded, adding, "Thanks to my Nike family!"

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