McDonald was a semifinalist in the boys’ singles of the 2012 Australian Open. In 2012, he reached a career high ranking in the ITF World Tour Junior Rankings of number 12 and won the 18s singles title at the 2012 Easter Bowl. While still a junior, he won the men’s singles in the Ojai Tennis Tournament in 2013 and also qualified for the 2013 Cincinnati Masters at age 18 by defeating top 100 players Nicolas Mahut and Steve Johnson. However, he lost in the first round of the main draw to fellow qualifier David Goffin. McDonald was listed as the No. 1 player coming into college according to the ITA. As a freshman at UCLA, he was named a Singles All-American and the Pac-12 Freshman of the Year. McDonald was also a quarterfinalist at the NCAA singles championship while compiling a 33–9 record during the season, including an 18–4 record in dual matches.
Rinderknech played college tennis at Texas A&M University. Rinderknech made his Grand Slam main draw debut as a wildcard at the 2018 French Open in doubles partnering Florian Lakat. He also entered as a wildcard the first rounds of the 2020 French Open on his singles main draw debut and doubles main draw partnering with Manuel Guinard and reached the second round in doubles.