Federer won the US Open five straight times from 2004 to 2008.
His run began in 2004, when he defeated Lleyton Hewitt in the final. He successfully defended the title against Andre Agassi in 2005, Andy Roddick in 2006, and Novak Djokovic in 2007. In 2008, he completed the streak by beating Andy Murray.
The achievement is especially notable because the US Open is played on hard courts, while Federer is often most closely associated with Wimbledon and grass-court tennis. During this five-year stretch, he also won Wimbledon four consecutive times from 2004 through 2007. His US Open streak produced 40 consecutive match victories at the tournament.
A common mix-up is Wimbledon: Federer also won Wimbledon five straight times, but that streak ran from 2003 to 2007. The 2004–2008 sequence belongs to the US Open, and it remains the Open Era record for consecutive men's singles titles there.