Andre Agassi celebrated his new status as world No. 1 by coming from behind to beat Andy Roddick 3-6, 6-3, 6-4 in the U.S. Clay Court Championships final on Sunday.
Agassi, the top seed, trailed by a set and a break but rallied to win his fourth title of 2003 and 58th of his career, moving him above Romanian Ilie Nastase to number seven on the all-time list.
It was also his fourth career win in as many matches against fellow American Roddick, who was the two-time defending champion in this event.
Agassi, who will be 33 on Tuesday, moved to the top of the rankings by crushing Austrian Jurgen Melzer on Saturday, but the 20-year-old Roddick started the final well.
Roddick, the second seed, was a lifetime 16-0 at the Westside Tennis Club and was impressive in winning the first set.
The youngster then broke in the first game of the second set and held for a 2-0 lead.
But his older opponent went on a run, winning five of the next six games to take over the momentum.
Agassi broke in the fifth game of the final set and never looked back, going on to complete his 23rd victory in 24 matches this year.