On Thursday, the pregnant tennis pro Serena Williams posted a video to Instagram of herself in a practice match, and needless to say, she still slays. Dressed in an all-black outfit, Serena's growing baby bump was very visible as she fiercely hit the ball to her opponent. The 35-year-old athlete might have been inspired to get back out on the court after attending sister Venus Williams' match at the French Open earlier this month.