Roger Federer won his 101st career title, and second of 2019, as he beat John Isner 6-1, 6-4 in the Miami Open final on Sunday.

The 37-year-old was in supreme form and lost just three points on his serve in the entire match.

Isner lost his first service game of the contest and could never get a grip on the match because of Federer's consistency.

Down 4-3 in the second set, Isner called his trainer, and he looked increasingly uncomfortable thereafter.

To his credit, the American hobbled back out on court to serve to stay in the match at 5-4 down, but Federer duly got the second-set break he needed to claim the title in Florida. 

Federer is a difficult enough opponent at the best of times, but especially when he gets an early advantage.

Isner's serve, as his fiercest weapon, was always going to be crucial to his success as he attempted to defend his title.

But he was sloppy with the ball in hand in the first game of the match and immediately went 1-0 behind after Federer piled on the pressure with a fine passing shot:

A love hold in his second service game would have come as a relief for Isner, but the damage had already been done as Federer was faultless.

And it did not last, as some Isner errors and Federer brilliance combined to see the Swiss legend break again for 4-1, and again to seal the opener in just 24 minutes:

A comeback never seemed likely from that point. As vulnerable as Isner's serve looked, Federer's looked unbreakable.

Another hold to love for the 20-time Grand Slam winner opened the second set, and Isner responded with some similarly efficient serving.

At 4-4 in the second, a tiebreak looked to be on the cards.

But then the 33-year-old aggravated the foot injury he had just been treated for and hopped in pain behind the baseline:

A retirement looked like it could be forthcoming, but instead Isner returned to serve at 5-4 behind.

The game was up, though, as the pace was gone from Isner's serve and he could barely move around the court.

He produced an impressive point to save Federer's first championship point, but he then went long to hand his opponent a fourth Miami Open title.