Serena Williams is a weight-loss champ!

The tennis star showed off her stunning weight loss with this sexy selfie shot just two weeks after the she gave birth to daughter Alexis Olympia Ohanian. Williams posed in front of her bathroom mirror wearing her tightest, sexiest jean shorts and guess what ... they fit!

After she and fiance Alexis (yes, same name as the baby) Ohanian, the co-rounder of Reddit, welcomed their daughter in a Palm Beach hospital on September 1, the pair decided to launch an Instagram account for their daughter which already boasts more than 33K followers after only two posts. We're guessing both numbers will grow -- as will this adorable baby! -- in no time ...