John McEnroe was backing other young ATP players over his compatriot Frances Tiafoe.
McEnroe is a multiple Grand Slam champion, and knows what it takes to win the biggest titles in the sport.
The former world number one also has experience of mentoring younger players, with McEnroe captaining at the Laver Cup for seven years before handing over the baton to Andre Agassi this year.
This includes McEnroe captaining Tiafoe as part of Team World for the first time in 2017.