The fourth-seeded Murray looked sluggish in the last two sets and couldn't overcome a lack of sleep following his three-set win over James Blake that ended at 1:45 a.m. local time Thursday in the previous round.

"It's obviously limited recovery after a long match," the 22-year-old Murray said. "It's 4 a.m. by the time you get to bed. So it's not perfect preparation for a match. But you still come out and you try and give it your best shot. Wasn't good enough."

Murray, who won his sixth title of the season last week in Valencia, had never lost a set against Stepanek in their three previous meetings.

After dominating the first set, the Wimbledon semifinalist was broken early in the second and never recovered after that. Stepanek, who reached the final in Paris in 2004, clinched the win with a service winner and will next face either Fernando Gonzalez or Juan Martin Del Potro.

"I didn't feel I played great in the first set," Murray said. "I lost my serve from up 40-15 in the beginning of the second, and then he played better after that."

Murray returned to competition last week in Valencia after being sidelined following the U.S. Open in September due to a left wrist injury.

He said his overall fitness was good and that he will be in a good shape after a few days off.

"I played seven matches in the space of eight or nine days and that was exactly what I needed at this stage of the season after having a break," he said.

Murray will now train at the Queen's Club to get prepared for the season-ending ATP World Tour Finals in London later this month. The Scot is one of seven players who have already qualified for the tournament after Nikolay Davydenko of Russia booked his place Thursday despite losing to Robin Soderling.

Defending champion Jo-Wilfried Tsonga needed only 52 minutes to reach the quarterfinals, easily beating Gilles Simon of France 6-2, 6-3 and can still grab the last available spot in London. Tsonga never faced a break point and broke his opponent's serve three times.

Tsonga, who beat three top-10 opponents last year on his way to the title in Paris, will next face either second-seeded Rafael Nadal or 14th-seeded Tommy Robredo. He will travel to England if he defends his title in Paris.

"I'm not thinking about London," said Tsonga, who had 13 aces Thursday. "I'm thinking about defending my title, ore even more, about going to get a new title instead of thinking about London."

Simon, who injured his right knee in a two-hour, three-set match against Ivan Ljubicic in the previous round, was hampered from the start by the wound and struggled to return Tsonga's powerful serves.

Soderling also has slim hopes of qualifying for the prestigious event following his victory over former champion Davydenko 6-3, 3-6, 6-4. Despite his loss, the sixth-seeded Davydenko secured his place following seventh-seeded Fernando Verdasco's loss to Marin Cilic 3-6, 6-3, 6-4.

Soderling's next opponent will be third-seeded Novak Djokovic, who defeated French qualifier Arnaud Clement 6-2, 6-2.

"I was moving better (than yesterday)," Djokovic said. "I was using the chances to go to the net and to make some winners when they have been given to me. And I gained the control of the match in the early stages of the first set."

Djokovic, coming off a win over top-ranked Roger Federer in the Swiss Indoors final last week, reached the quarterfinals for the first time after winning 80 percent of the points played on his first serve. Clement saved two match points before Djokovic took the match when his opponent put a forehand into the net.

"I want to do well here," Djokovic said. "I know it's a very important tournament and I just hope to maintain the high level of performance I had in the last two months."

Nadal, who saved five match points to reach the third round, will face Robredo later Thursday.

Julien Benneteau, who upset top-ranked Roger Federer in the previous round, lost to 15th-seeded Gael Monfils 6-4, 6-3. Monfils will play Cilic in the quarterfinals.