Mumbai, Jan. 14 -- Alex Michelsen swings a baseball bat left-handed. He kicks a football with his left foot. But he plays tennis right-handed. It's a switch that makes the 20-year-old American a tricky opponent, as world No.12 Stefanos Tsitsipas experienced first-hand at the Australian Open on Monday.

Playing at the John Cain Arena in Melbourne Park, Michelsen pulled off a 7-5, 6-3, 2-6, 6-4 first round upset over the Greek 11th seed to pick up his first-ever win over a top 20 player at a Grand Slam. Central to the triumph was his solidity and angles he was able to produce from his backhand side.

Tsitsipas, the 2023 Australian Open finalist, boasts a game that revolves around a powerful forehand and big serve. His backhand, an elegant one...