Andy Murray, Novak Djokovic win in straight sets in Mason

Novak Djokovic, Andy Murray and Roger Federer won their opening matches at the Western & Southern Open in straight sets Wednesday, getting accustomed to the heat after spending the last two weeks in London and Canada.

Djokovic got the bronze medal at the Olympics in London, then won the Rogers Cup in Toronto on Sunday night. He was a little off in his opening set on a court baked in sunshine and 86-degree heat, before pulling away from Andreas Seppi of Italy 7-6 (4), 6-2.

"Sometimes it's really hard to try to stay fit for every single tournament and try to perform your best," Djokovic said. "I mean, in the last three, four weeks, I have changed three different cities, places, surfaces, conditions. I'm still trying to figure out where I am."

Murray had the best moment of his career at Wimbledon, winning the Olympic gold on home soil. He had to withdraw from the Rogers Cup because of a sore knee, which he blamed on the transition from grass to hard courts.

Murray, the defending champion in Cincinnati, moved around the court well during his 6-2, 6-4 win over Sam Querrey. The American repeatedly missed open shots while falling behind and managed only two break points during the match, both of which Murray saved.

"It felt fine," Murray said of his knee. "I moved well today. It still was giving me a little bit of trouble in practice for a couple of days before the tournament, but it felt fine, much better on the court today. I moved well, so I'm hoping it won't be a problem."

Federer had no trouble in his evening match against Russia's Alex Bogomolov, winning 6-3, 6-2 in exactly one hour. He served 12 aces and didn't face a break point until the final game of the match.

Federer skipped the Rogers Cup, so it was his first match back on a hard court.

"It's nice to be back on the hard courts," Federer said. "I served really well. He struggled to get into some rallies."

On the women's side, top-seeded Agnieszka Radwanska of Poland also advanced to the third round with a 6-4, 6-3 win over Sofia Arvidsson of Sweden. Venus Williams moved on with her second three-set victory in two days.

Yaroslava Shvedova of Kazakhstan quit her match while trailing in the second set, overcome by the heat, and also dropped out of her later doubles match.

Radwanska, who received a first-round bye, felt a little rusty.

"The first match is always more difficult, with the different balls and conditions," she said. "I was happy to get through it, especially since it was very hot. Hopefully, I'll better (Thursday)."

Radwanska, who lost to Serena Williams in the Wimbledon final and is ranked No. 3 in the world, will meet Sloane Stephens of the United States, who got into the tournament as a wild card.

"I'll just go out and play my game," Stephens said, adding with a smile, "I'm not going to tell you how I'm going to play, because she'll probably read this and know how to play."

Venus Williams won the gold medal in doubles with her sister in London and arrived for the tournament in suburban Cincinnati upbeat. She needed three sets and 2 hours, 23 minutes to win her opening match Tuesday, then followed it with a 2-6, 6-3, 6-2 victory over Russia's Chanelle Scheepers in the afternoon heat that lasted an hour and 46 minutes.

After Scheepers' long return ended it, Williams briefly raised her arm in celebration, walked slowly to the net to shake hands, and sat down and rubbed her forehead with both hands.

Eleventh-seeded Dominka Cibulkova withdrew with an injury after losing the first set in a tiebreaker against qualifier Andrea Hlavackova of the Czech Republic. China's Shuai Peng also advanced with a 6-3, 6-4 win over Roberta Vinci of Italy.

In men's action, No. 10-seeded Mardy Fish of the United States advanced to the third round by defeating Carlos Berlocq of Argentina 6-3, 6-1. Serbian Victor Troicki moved on to the third round with a 6-2, 6-0 win over Australian Lleyton Hewitt. Nikolay Davydenko of Russia beat Florian Meyer of Germany 6-3, 6-3.

Fish was happy to advance relatively easily against an unfamiliar opponent while still working back into form after a surgical procedure to correct a heart condition in May.

"It was nice to get on and off quickly, especially with a win," said Fish, who'd never played Berlocq in singles. "You also can get on and off quickly with a loss. It's somewhat tricky. You never know what to expect. I played as well today as I have all summer. He's a good player. If you're not on top of your game, you could be in trouble."