PARIS (AP) – Already at the center of tennis’ gambling probe, No. 4-ranked Nikolay Davydenko was criticized for his play at a second consecutive tournament Thursday, when his poor serving during a loss at the Paris Masters drew a rebuke from the chair umpire.

Davydenko, the defending champion, finished with 10 double-faults and 36 unforced errors in a 6-2, 6-2 third-round defeat against No. 22 Marcos Baghdatis. The Russian was booed during a match in which he lost serve five times.

A week ago, Davydenko was fined $2,000 by the ATP for “lack of best effort” during a 1-6, 7-5, 6-1 loss to then-No. 102 Marin Cilic at the St. Petersburg Open. Davydenko was given a hard time during that match by the chair umpire, too.

ATP spokesman Nicola Arzani said Thursday the tour didn’t think anything was wrong with what Davydenko did in Paris, so no action will be taken against him.

Chair umpire Cedric Mourier spoke to Davydenko at a changeover during the Baghdatis match, asking him what was wrong with his serve. Davydenko responded by asking what else he could do.

Davydenko had said Wednesday he was hampered by a sore elbow, but he didn’t give a direct answer when Baghdatis asked him what was wrong as they shook hands at the end of the match.

“I cannot serve,” Davydenko said later. “That was happening in St. Petersburg. I don’t have pain really. I have no pain in my elbow. I need to find what’s the reason I cannot really serve.”

In August, online gambling exchange Betfair voided all bets on a match after Davydenko withdrew against 87th-ranked Martin Vassallo Arguello in the third set because of a foot injury. The ATP is still looking into that match.

“I’m not thinking about the stories and rumors about him,” Baghdatis said. “I don’t know if they are true or not. I just try to play my game and remain focused.”

Baghdatis saved six break points en route to setting up a quarterfinal matchup against eighth-seeded Tommy Robredo, who beat 11th-seeded Guillermo Canas 7-5, 7-5.

In other action, No. 2 Rafael Nadal beat Stanislas Wawrinka 6-4, 6-3, while Andy Murray stayed in contention for a spot in the season-ending Masters Cup by beating French veteran Fabrice Santoro 6-4, 6-2.

Fifth-seeded David Ferrer of Spain and 10th-seeded Richard Gasquet of France also advanced in straight sets.

Gasquet ousted sixth-seeded James Blake of the U.S. 6-4, 6-4, and Ferrer defeated 12th-seeded Tomas Berdych 6-4, 6-2, ending the Czech’s hopes of qualifying for the Masters Cup.

Later, Roger Federer was to face David Nalbandian. The Argentine beat Federer last month in the Madrid Masters final.

Federer, Nadal, Novak Djokovic, Davydenko, Andy Roddick and David Ferrer have already qualified for the Masters Cup. The two remaining spots will be decided in Paris.

AP-ES-11-01-07 1539EDT