Juan Martín del Potro is an Argentinian former professional tennis player known for winning the 2009 US Open, defeating Rafael Nadal and Roger Federer. He also earned an Olympic bronze and silver medal and led Argentina to a Davis Cup win in 2016.
This is based on winning 2 head-to-head matchups with other famous people, but also losing 17 head-to-head matchups.
Most recently Juan Martín del Potro lost a matchup to John Mayer (#380) voted by someone from United States.