Radek Stepanek of the Czech Republic was the only seeded player to fall on a rain-interrupted opening day of the Toronto Masters on Monday.
Spain's Feliciano Lopez proved to be Stepanek's conqueror, beating the 11th seed 4-6, 6-3, 6-4, on a day that was without draw cards Roger Federer, Rafael Nadal and Novak Djokovic in singles action.
All three, who are launching their North American hardcourt campaigns in Toronto, have been granted first round byes in the US$2.6 million tournament.
"Obviously this is the surface that suits my game most," said Djokovic, who will open his title defence with a second round match against Canada's Frank Dancevic.
"It is my most preferred surface, the surface where I did my best results and biggest achievement of my career," the Australian Open champion added.
"So I think it is enough reason to expect to do well in the hardcourt season.
"Defending this title I have a lot of responsibilities and expectations but it is a challenge."
While the men's top three did not play on Monday, five other seeds advanced to the second round with ninth-seeded Swiss Stanislas Wawrinka beating the rain that delayed play for almost two hours with a 6-4, 7-6 victory over Italy's Simone Bolelli.
Wawrinka was joined in the second round by 10th seeded Frenchman Richard Gasquet, who disposed of Davis Cup teammate Michael Llodra 6-2, 4-6, 6-3.
"I know him well, I played Davis Cup with him and I practise with him, so it's always difficult to play against a countryman," said Gasquet.
"It was ok for me to play three sets. For sure I prefer to win in two but I'm happy to get the win."
Spanish 12th-seed Tommy Robredo, 14th-seed Fernando Gonzalez of Chile and 15th-seed Mikhail Youzhny of Russia all advanced with straight set victories.
Gonzalez, winner of two clay court events this season, outclassed France's Julien Benneteau 6-2, 6-1, while Robredo brushed past Canadian wildcard Frederic Niemeyer 7-6, 6-1 and Youzhny beat Italy's Andreas Seppi 7-6, 6-2.
Germany's Nicolas Kiefer and France's Arnaud Clement also battled their way to first round wins.
Kiefer beat American Mardy Fish 7-5, 7-6 while Clement outlasted Colombia's Alejandro Falla 7-5, 3-6, 6-2.
In Los Angeles, unseeded Australian Samantha Stosur scored the biggest upset in the opening round of the Los Angeles Classic on Monday, easing to a 6-1, 6-1 victory over 12th seeded Israeli Shahar Peer.
Sybille Bammer and Sania Mirza enjoyed routine wins, while Virginie Razzano joined Peer as one of the early surprise losers.
The 13th seeded Frenchwoman was beaten 6-3, 6-3 by Hungary's Melinda Czink.
(Agencies via Shanghai Daily July 23, 2008)