CINCINNATI - Olympic champion Andy Murray was sent crashing out of the Cincinnati Masters on Thursday, falling 6-4, 6-4 to French lucky loser Jeremy Chardy.

Britain’s Murray won a match in Toronto last week before quitting with a knee injury but had looked impressive in his opener here against American Sam Querrey.

But the 25-year-old Murray was distinctly under-cooked against Chardy and his 16th unforced error of the second set sent the Frenchman into the last eight. “This was like my second or third match in the hard court. I played well yesterday; didn’t play so well today,” said Murray. “Sometimes I’ve won tournaments in the buildup (to a major) and it hasn’t helped me. That doesn’t normally have that much bearing. But I would have liked to have done a bit better this week,” he said, with the US Open on the horizon.

Four-time champion and top seed Roger Federer turned in another flawless performance, schooling Australian teenager Bernard Tomic 6-2, 6-4 with 27 winners. “Overall I’m happy. But it’s hard to judge my game in these quick conditions,” said Federer, the Olympic silver medallist, who however admitted that his serve was “a bit off.”

“It was a good performance, I’m playing as well as I want to right now,” said the Swiss great. Second seed Novak Djokovic barely broke a sweat against Nikolay Davydenko, who was nursing a shoulder injury and only lasted 30 minutes before quitting after Djokovic took the first set, 6-0.

Davydenko had 10 unforced errors and eight double-faults. “This is not the way to win a match, it was clear that he was struggling physically,” Djokovic said. “I just hope he will be fit for the US Open.”

Canadian Milos Raonic upset fifth seed Tomas Berdych with 20 aces in a 6-4, 2-6, 6-2 win.  Olympic bronze medallist Juan Martin del Potro, who missed 2010 due to right wrist surgery, had troubles with his left wrist, but pushed through the pain to notch a 7-6 (7/2), 2-6, 6-1 win over Serbia’s Viktor Troicki.

Tenth seed Mardy Fish continued to perform well on his home cement courts, beating Czech Radek Stepanek 6-3, 6-3 with seven aces and 23 winners. Fish will next play Federer. Serena Williams, coming off a double Olympic gold medal-winning performance in London, said she was feeling the pace of a hectic schedule after a lethargic display in her 6-3 6-0 win over Urszula Radwanska on Thursday. Williams made a series of unforced errors and showed little movement as she laboured her way through a 70-minute match in humid conditions to earn a spot in the quarter-finals at the Cincinnati Open.

“I was out there and I did the best I could today. I was happy to get through that match,” said Williams, who won six consecutive games to finish off the match. “It was just energy. I have been playing a lot, been travelling a lot, been training a lot. It’s been a really big summer. Singles and doubles is a tough schedule.” Since the start of Wimbledon in June, Williams has played 30 matches, with 19 in singles play and 11 in doubles.

But Williams expects to be in better shape for her quarter-final matchup against Wimbledon semi-finalist Angelique Kerber.

“I think it’s just a oneday thing. I will get some rest,” said Williams, who retained the Olympic tennis women’s doubles gold with her older sister Venus in London. The 14-times grand slam winner did spare a thought for her vanquished opponent Radwanska, who is the younger sister of Polish world number three Agnieszka Radwanska. “I think Urszula has worked really hard, and me being a younger sister and Urszula being a younger sister, I’m always looking for her to do well and hoping she does really well.”

Sister Venus also booked her place in the last eight with a routine 6-3 6-0 dispatching of Italian Sara Errani which earns her a clash with U.S. Open champion Samantha Stosur.

Australian Stosur dealt with Russian Ekaterina Makarova 6-1 6-3 while Agnieszka Radwanska needed three sets to deal with determined American Sloane Stephens 6-1 4-6 6-4.

3rd round results:

Men: Milos Raonic (CAN) bt Tomas Berdych (CZE x5) 6-4, 2-6, 6-2. Mardy Fish (USA x10) bt Radek Stepanek (CZE) 6-3, 6-3.  Juan Martin del Potro (ARG x6) bt Viktor Troicki (SRB) 7-6 (7/2), 2-6, 6-1. Stanislas Wawrinka (SUI) bt Kei Nishikori (JPN x14) 6-3, 6-3. Jeremy Chardy (FRA) bt Andy Murray (GBR x3) 6-4, 6-4. Roger Federer (SUI x1) bt Bernard Tomic (AUS) 6-2, 6-4. Marin Cilic (CRO x12) bt Pablo Andujar (ESP) 7-6 (7/4), 6-2. Novak Djokovic (SRB x2) bt Nikolay Davydenko (RUS) 6-0, retired, shoulder.

Women 3rd rd: Agnieszka Radwanska (POL x1) bt Sloane Stephens (USA) 6-1, 4-6, 6-4. Petra Kvitova (CZE x4) bt Peng Shuai (CHN) 6-2, 6-2. Angelique Kerber (GER x5) bt Andrea Hlavackova (CZE) 6-4, 7-6 (7/5). Serena Williams (USA x2) bt Urszula Radwanska (POL) 6-4, 6-3. Samantha Stosur (AUS x3) bt Elena Makarova (RUS) 6-1, 6-3. Venus Williams (USA) bt Sara Errani (ITA x7) 6-3, 6-0.