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2016 - After a successful college career at UCLA, Mackenzie McDonald decided to turn professional.
The American proved capable of playing on the pro level in his first season, having reached three Challenger semi-finals that year.
However, the highlight of McDonald's first pro season was a Grand Slam debut appearance at the US Open, wbere he blew a two-set lead against Czech Jan Satral in the first round.
2017 - McDonald won his maiden Challenger title at the Fairfield Challenger after defeating fellow compatriot Bradley Klahn in the final.
The American also entered the top-200 for the first time in his career.
2018 - McDonald qualified for his first Australian Open before he clinched his maiden Grand Slam win after beating Elias Ymer in the first round.
The American impressed in his Wimbledon debut, having reached the round-of-16 before losing to 2016 Wimbledon runner-up Milos Raonic.
McDonald entered the top-100 for the first time in his career.