Federer reaches Miami Open fourth round

Roger Federer of Switzerland returns a shot against Juan Martin Del Potro of Argentina during the Miami Open at Crandon Park Tennis Centre in Key Biscayne, Florida. (Al Bello/Getty Images/AFP)

Del Potro always enjoys plenty of crowd support in Miami, which has a large Argentine community, and it was the same story again with football-style chants of support ringing out for the 28-year-old on a packed Crandon Park centre court.

It was the pair's first meeting since 2013 and having won 15 of the previous 21 encounters, Federer was favourite - but the crowd factor gave the third round match an added edge.

"Shortly before I walked out to the court you could sense the atmosphere. That's when I told myself, Just be prepared for something different, you know. It was different," Federer said.

He was forced to save four break points in the first set but he got ahead with a thundering forehand to take a 5-3 lead and served out for the set.

The Argentine had a chance to turn things around when he had a break point when down 4-3 in the second set but Federer, moving well and looking full of confidence, held firm and wrapped up the match in one hour and 22 minutes.

"I felt like I was in control and I was able to generate more chances than he did," Federer said.

"I felt like he got his chances a little bit out of nowhere, maybe because I dropped my level ever so slightly and gave him few easy points, and that's how he sort of got more chances on my serve.

"I feel like I earned it more. I was more the aggressor. It was more on my racquet, and I like it that way," added the Swiss, who won his 18th Grand Slam title at the Australian Open in January.

Federer, whose successful return from a six-month injury layoff has also included a win at Indian Wells this month, will face 14th seeded Spaniard Roberto Bautista Agut in the next round.

Czech Tomas Berdych, Miami finalist in 2010, defeated Gilles Muller 6-3, 6-4 while Federer's compatriot Stan Wawrinka was scheduled to face Tunisian Malek Jaziri later on Monday.