LONDON (AFP) Rafael Nadal was sent crashing out of the ATP World Tour Finals in a straight sets defeat to last years finalist Nikolay Davydenko on Wednesday. The Russian won 6-1, 7-6 (7/4) in an hour and 47 minutes at Londons O2 Arena to send the Spanish world number two tumbling out of the season-ending championships at the group stage. Davydenkos powerful, accurate ground strokes tore Nadals game apart in the opening set, and though the Australian Open champion recovered some form in the 80-minute second set, it was too late to stop the world number seven from claiming victory. Nadal went into the match with a 4-3 lead over Davydenko, though the Russian had won their previous three meetings on hard courts like the O2 Arena - including a 7-6 (7/3), 6-3 win in the Shanghai final last month. The first set saw Nadals game destroyed by his opponent, who dominated the play with his impressive shot-making, sending the left-hander scampering round the court. Nadal, 23, won the toss, chose to receive and was swiftly 3-0 down. Davydenko, 28, kicked off the match with an ace and took the first game, then converted a break point on Nadals serve when the Spaniard misfired. Davydenko then held serve before Nadal won the fourth game to love. After the Russian held serve, he broke Nadal to love as the Mallorcans serve crumbled. Davydenko held three set points and sealed it with an ace to wrap up the first set in 27 minutes. Nadal was break point down in the first game of the second set but recovered to win it on the deuce. Davydenko held serve and held break point again on Nadals serve but the Spaniard finally won the game thanks to a rare Davydenko error. The Australian Open champion took a 15-40 lead next game but the serving Russian pulled it back to deuce and won it. Nadal served the next game to love as he revived his hopes. He then held a key break point in the eighth game. It went to deuce when Nadal shot just long. Nadal held break point again when Davydenko hit the frame of the racquet and finally broke his opponent when the Russian shot long, the Mallorcan dropping to his knees in celebration. That fired up Nadal further, who served the next game to love to lead 5-4. However, Davydenko held serve and broke next game as Nadal double-faulted and hit the net twice to leave the Russian serving for the game. But Nadal went 15-40 up with an excellent shot down the line and broke when Davydenko hit the net, taking the set to a tie-break. At 5-3 up, Davydenko, after an extraordinarily long rally, hit the net - one of only two net points lost out of 16 in the whole game. That gave Nadal hope and he successfully challenged a line call to keep it at 5-4. However, he hit his next service return into the net and Davydenko sealed victory with a forehand winner. In the final round of Group B games, Davydenko plays Swedens Robin Soderling, who has already qualified for the semi-finals, while Nadal takes on Serbias titleholder Novak Djokovic.