Roger Federer delighted his home fans in Geneva, as he and doubles partner Alexander Zverev defeated Jack Sock and Denis Shapovalov to give Europe a 3-1 lead over Team World after the opening day of the third Laver Cup.
The 38-year-old Swiss and the 22-year-old German won 6-3, 7-5 at the Palexapo indoor venue.
Sock, one of three United States players in Team World, had earlier defeated Fabio Fognini 6-1, 7-6 (7/3) in the singles to bring John McEnroe's visitors level after Dominic Thiem's opening win against Shapovalov.
But Stefanos Tsitsipas restored Europe's advantage by beating Taylor Fritz in a super tie-break to win 6-2, 1-6, 10-7, before Federer and Zverev combined to put Europe in control in an event they have won on both previous occasions.
Earlier in the day, Thiem saved three match points before beating Canada's Shapovalov in the opening tie.
The two-time French Open runner-up recovered from 9-7 down in a super tie-break to win 6-4, 5-7, 13-11.
Acton continues tomorrow with three more singles and one more doubles match.