American Christian Vande Velde won the fourth stage of the Paris-Nice race as
|Vande Velde of team Garmin Slipstream breaks away from the pack [GALLO/GETTY]
favourite Alberto Contador made up lost ground with a sharp attack in the last climb.
Garmin-Slipstream's Vande Velde broke away from a small group with some 20 kilometres remaining in the 173.5-km stage from Vichy and never looked back.
He crossed the line 14 seconds ahead of Frenchman Jonathan Hivert of the Skil-Shimano team and Lampre's Mirco Lorenzetto of Italy, who were second and third respectively.
Chavanel retains lead
"I had not planned this attack, I kind of found myself in front by chance," Vande Velde, fifth overall in last year's Tour de France, said on Wednesday.
"It's fantastic, it's the first time in my career that I won in this fashion."
Sylvain Chavanel of France retained the overall lead despite suffering in the ascent of the Cote de Rochetaillee and losing 27 seconds to Contador, who attacked two km from the summit.
Quick Step's Chavanel, who seized the yellow jersey in spectacular fashion on Tuesday, could not cope with the Spaniard's sudden acceleration and his overall lead over Spain's Juan Manuel Garate dwindled to six seconds.
Contador, who will be on his favourite ground on Friday in the summit finish at the Montagne de Lure, moved up to fourth overall, 36 seconds off the pace.
"When he attacked, I did not want to be in the red, I did not panic," Chavanel said.
"I had a tough day yesterday but I expected to be better today. However, I still have a slim margin."
Earlier, a group of seven, including Vande Velde, broke away after 67 km and built up a two-minute gap until, at the head of the peloton, the Quick Step team stepped up a gear at the foot of the Cote de Saint-Bonnet-les-Oules, one of four climbs in the last 55 km.
Vande Velde jumped out of the leading group 20 km from the finish, just before three French counter-attackers closed in.
Pierre Rolland, Christophe Le Mevel and Geoffroy Lequatre were joined by Russian Alexandr Kolobnev to chase the American as the other breakaways ran out of steam.
They were eventually swallowed by the bunch, which was shaken by Contador's attack in the final climb.
The Astana leader could hurt his rivals again on Thursday as the fifth stage features seven ascents, including a category-one climb.
"It is still far from being over," Astana sports director Alain Gallopin said.
"The attack was not planned but Alberto is a rider who likes to put on a show."