Roger Federer beat Ivan Ljubicic in three tight sets to win the Nasdaq-100 Open for the second straight year.
Federer has been beaten only once all year
Ljubicic, the world number six, battled gamely throughout, taking all three sets to tie-breaks.
But Federer was able to raise his game when it mattered, winning the key points to claim a 7-6 (7-5) 7-6 (7-4) 7-6 (8-6) win.
The victory gave Federer the Indian Wells-Miami Masters Series double for the second year in a row.
"To win back-to-back like this is unbelievable," said Federer.
"I never thought I'd do it again. It really feels great.
"It was tough today, he made me work very hard.
"He could have pushed me further if he'd played better on big points in the tie-breaks.
"But he was going for big serves with great variation. He made me work but I expected that - three tie-breaks is the most extreme you can have."
The Nasdaq-100 Open is often referred to as tennis' unofficial fifth Grand Slam and for Ljubicic it would have been the biggest title win of his career.
Despite the tight scoreline, Ljubicic never quite threatened to upset the form book.
He matched Federer blow for blow in the first set but the world number one took the tie-break 7-5.
It appeared Federer might run away with it when he took the first break of serve of the match midway through the second set.
Ljubicic battled back to earn another tie-break and then led by a break in the third set.
But he was unable to take advantage of his opportunities as Federer fought back in the third to wrap up victory.
"I played well but it's still a loss; it feels a bit rough," Ljubicic told reporters.
"He never misses in tie-breaks and comes up with his best shots when it's important."