It was not until the third set that Federer was allowed to dictate matters in pursuit of his sixth Grand Slam singles title - one that would make him the first man successfully to defend both the Wimbledon and United States championships since Donald Budge in 1938.
Agassi, who had played three five-set matches in a row, was watched by one of his admirers, Lance Armstrong, the seven-times winner of the Tour de France. And Agassi made the world No 1 look less than supreme for the best part of three sets. It was only then that Federer sprinted away to triumph, 6-3, 2-6, 7-6, 6-1 after 2 hours, 20 minutes.
Agassi matched Federer move for move in the opening five games, only to be broken for 4-2. The tenacious American then saved seven set points - three on his own serve at 2-5, and five more as Federer served for the set. Serving solidly, scurrying, retrieving, and causing his opponent to make errors, Agassi won some remarkable points with angled drives and exchanged drop-shots.
Although Federer converted his eighth set point with a service winner after 34 minutes, Agassi, emboldened by his ability to make his opponent work for points, took a 3-0 lead in the second set.
He broke for 2-0 with a searing cross-court forehand and then again demonstrated his fighting spirit by erasing three break points in the third game, Federer returning a second serve long on Agassi's first game point. Agassi broke a second time to level the match after 67 minutes, converting his second set point at 5-2 with another punishing service return.
By now, Federer's normally dominating style was wavering. It took an Agassi break for 4-2 in the third set, returning a second serve, to jolt Federer into concerted action. He broke back with a cross-court backhand from an Agassi net-cord - one of the Swiss star's few decent backhands for several games - and held for 4-4.
Agassi frustrated Federer by saving four break points at 5-5, but when the set went to a tie-break Federer unleashed his shots as confidently, just as he did in his second-set semi-final shoot-out against Lleyton Hewitt. Federer, who did not drop a point in that one, cracked Agassi 7-1.
That was the prelude to Federer's ferocious finish. He won the opening five games of the fourth set, and although Agassi delayed the inevitable in the next game, Federer then held serve to win the match.Reuse content