Nadal, enjoying his 30th consecutive week at No. 1, had a bye in the first round before overwhelming Berrer, a qualifier ranked No. 112 on the ATP Tour. Nadal lost just five points in seven service games and broke Berrer five times.
"I think I am playing well. I played a good match today,'' said the Spaniard, who will meet Dmitry Tursunov of Russia in the third round.
"For me it was perfect,'' Nadal said. "I played a very comfortable match. I had thebreak in the first game of both sets. That's really important. I felt well on the court, playing good.''
The 26th-ranked Tursunov struggled to a 7-6 (5), 4-6, 6-3 win over American qualifier Michael Russell.
Andy Roddick, the No. 7 seed, didn't play quite as well against Austrian qualifier Daniel Koellerer, but still managed a 6-3, 7-6 (3) win. Fellow American Sam Querrey won, too, 6-4, 6-3 over No. 18 Radek Stepanek.
Koellerer is getting a reputation for gamesmanship and Roddick said he "definitely tried everything in his power to get a win. I kind of knew going in that I'd have to stay focused and stay the course and not get caught up in the histrionics.''
Earlier in the day, defending champion and third-seeded Novak Djokovic also advanced to the third round with a 7-5, 6-4 win against Martin Vassallo Arguello of Argentina.
Djokovic struggled at the start of the season, but is coming off a tournament title at Dubai last month.
"Winning Dubai meant a lot for my confidence level and for my game overall,'' he said. "I've changed my racquet. Probably that was the big reason for mental instability in certain stages at the start of the year. I was thinking about that more than my game. Luckily for me, it has changed.
"The quality is there. The game is there. The fitness is getting much better. It's just a mental ability to play the best tennis. My confidence has raised in the last month and a half. There is room for improvement, but I'm taking it step by step.''
American Mardy Fish, last year's runner-up, lost to Jeremy Chardy of France, 7-6 (4), 7-6 (1).
Fish, who beat Nikolay Davydenko, David Nalbandian and Roger Federer en route to last year's final, had beaten Chardy two weeks ago at Delray Beach, Fla., where he won the title.
But he said Sunday he "really didn't think I played the big points very well. I just missed some shots I haven't missed in the past month. I've been playing some great tennis (recently), really hitting the ball well in practice and coming in here with more confidence than I've had coming into any tournament ever.''
In the women's draw, top-seeded Dinara Safina, No. 4 Vera Zvonareva of Russia, No. 9 Caroline Wozniacki of Denmark and unseeded American Jill Craybas all won their third-round matches.
Safina, who will move to the top of the WTA Tour rankings if she reaches the final round, beat Shuai Peng of China, 7-5, 6-4; Zvonareva, on track for a possible semifinal meeting with Safina, was a 6-3, 6-1 winner over Czech Petra Kvitova; and Wozniacki, Zvonareva's potential quarterfinals foe, beat Kaia Kanepi of Estonia, 6-3, 3-6, 6-3. Craybas, No. 102 in the WTA Tour rankings, ousted Nicole Vaidisova of the Czech Republic, 6-4, 6-3.
In other men's matches, No. 8 seed Juan Martin del Potro also moved into the third round with a 6-7 (6), 6-3, 6-1 win over American wild card Ryan Sweeting, but 6-foot-9 John Isner upset ninth-seeded Gael Monfils of France, 6-7 (5), 6-4, 6-4.
