Spain's Rafael Nadal continued his quest for his first Miami title, routing Fabio Fognini 6-2, 6-2 to advance to the quarterfinals of the Sony Open Tennis.

The Italian couldn't find the court in the early going of Tuesday night's match, making 10 unforced errors in the first three games to allow the world No. 1 to race out to an early double-break lead.

By contrast, Nadal came out strong from the outset, hitting heavy topspin ground strokes off both sides - as well as backhand slices - with depth and precision.

The second set followed a similar script and the drama-less contest came to a quick end in just over an hour, Nadal's third straight comfortable victory at this year's Miami tournament.

Besides his strong play, Nadal also pleased his fans by declaring himself fully recovered from the back injury he suffered in late January in the Australian Open final, in which he was upset by Switzerland's Stanislas Wawrinka.

"Physically, I'm fine. Competing at the highest level with physical limitations is practically impossible and I'm happy I don't have to do it," Nadal said after his round of 16 victory, noting that he has regained full power on his serve and has not lost a single service game thus far at the Sony Open Tennis.

He said his focused and aggressive play was the key to the victory against Fognini.

"I played with rhythm, looking to win the point and for Fabio to hit from difficult positions," the three-time Miami finalist said.

"Fabio played good points, but also a lot of bad points. It was a strange match, but I had to concentrate on what I was doing, be businesslike and keep my errors down. Sometimes when the opponent is (giving away a lot of points), the tendency is to move backward and just put the ball in play and that would've been a mistake," Nadal added.

Next up for the top seed in the quarterfinals will be big-serving Canadian Milos Raonic, who moved through to the final eight with a 6-3, 6-4 victory Tuesday over Germany's Benjamin Becker.

Also Tuesday, Ukrainian Alexandr Dolgopolov surprised Wawrinka 6-4, 3-6, 6-1 and will next take on Czech Tomas Berdych, a 6-3, 7-5 winner over American John Isner.

In the bottom half of the draw, Swiss great Roger Federer, Japan's Kei Nishikori, Britain's Andy Murray and Serbia's Novak Djokovic all advanced Tuesday to the quarterfinals. EFE