NEW HAVEN, Connecticut (Reuters) - The top seeds in both the men's and women's events at the New Haven Open lost on Thursday as Russian pair Svetlana Kuznetsova and Nikolay Davydenko bowed out with quarter-final defeats.

World number six Kuznetsova was unable to shake off former number one Amelie Mauresmo of France, who staved off five set points in the opener on her way to a 7-6 2-6 6-3 upset win over the 24-year-old.

The Frenchwoman took the tiebreak 11-9 and after falling victim to Kuznetsova's strong service game in the second set, the two-time grand slam champion reclaimed the momentum to advance to the semi-finals of the final U.S. Open warm-up event.

Matching Mauresmo's big victory was American Sam Querrey, who overpowered Davydenko in a dramatic 6-3 3-6 6-4 triumph.

Querrey had 15 aces in defeating the world number eight and heads into next week's final slam of the year having 19 of his past 24 matches.

The tall American will try to keep his hot streak going in the semi-finals against Argentina's Jose Acasuso, who defeated Florent Serra 7-5 6-4.

Igor Andreev outlasted Leonardo Mayer 6-4 6-7 6-3 and will play Fernando Verdasco in the other semi-final after the second seed beat Jurgen Melzer 6-3 6-1.

On the women's side, Caroline Wozniacki dispatched Virginie Razzano 6-4 6-3 and will meet Flavia Pennetta, who beat Magdalena Rybarikova 6-2 6-2.

Elena Vesnina defeated fellow Russian Anna Chakvetadze 6-1 7-5 to set up a showdown against Mauresmo on Friday.

(Writing by Jahmal Corner in Los Angeles; Editing by John O'Brien)