The first man to win 20 Grand Slam men's singles titles in the Open era was Roger Federer from Switzerland. He accomplished this feat at the Australian Open in 2018, defeating Marin Cilic in the final to claim his 20th Grand Slam singles title. Federer's Grand Slam tally includes 8 Wimbledon titles, 6 Australian Open titles, 5 US Open titles, and 1 French Open title.