Tanner defeated Guillermo Vilas in three straight sets in the 1977 Australian Open (January) final, to win his first and only grand slam title. Tanner lost a five set match to Björn Borg in the 1979 Wimbledon final, which was the first Wimbledon final to be broadcast live in the United States as part of NBC's "Breakfast at Wimbledon". Tanner avenged this loss to Borg by beating him in four sets in the US Open quarterfinals two months later, a match where Tanner's 140 mph serve brought the net down during the fourth set. Tanner lost to Vitas Gerulaitis in the semifinals. Tanner described his 1979 US Open win over Borg and loss to Gerulaitis in his autobiography as "the highest of my highs and the lowest of my lows on a tennis court within two days of each other".