That theory was proved true on Friday, when Mackenzie McDonald won a set serving underhand. Seriously. Facing Canadian Peter Polansky at the Challenger event in Knoxville, TN, McDonald served ...

Mackenzie McDonald received congratulatory messages ... McDonald took to Instagram and shared a post consisting of two pictures. In the first picture, McDonald and Mateas can be seen all smiles ...

Season 3 of My Tennis Life follows CoCo Vandeweghe and Mackenzie McDonald to give an inside look at what happens when the pros walk off the court as they traverse the globe in search of ...