Belgian rider Gianni Meersman timed his attack perfectly to win the fourth stage of the Paris-Nice race on Wednesday, and Bradley Wiggins kept the overall lead despite Alejandro Valverde's late attack on the final climb.

Meersman was in sixth place as the final sprint was launched about 150 meters (yards) from the finish. But he chose an outside line to just edge out Grega Bole of Slovenia at the line, with Dutch cyclist Lieuwe Westra finishing third.

"I thought I was too far but the finish was uphill. I waited, waited and waited until the last moment and I sprinted," Meersman said. "I had a really good winter, the problems with my back and my left leg are over. I'm healthy now and I feel good in this team. They worked hard today and I dedicate my victory to them all."

Valverde's Movistar team helped him to the front on the last of five climbs. But Wiggins tucked in behind Valverde's wheel to quell his attack.

Wiggins retained his 6-second lead over American veteran Levi Leipheimer, with Tejay Van Garderen of the United States 11 seconds back in third. Valverde failed to make up any time on Wiggins, remaining 20 seconds back and dropping a place to seventh with Westra moving above him.

Five riders forged ahead after 18 kilometers (11.2 miles) on the undulating 178-kilometer (110.4-mile) stage, which featured two category 2 climbs and consecutive category 3 ascents up Cote d'Aubert le Cres and the short but steep Cote de Bourran up to Rodez.

Spanish rider Luis Angel Mate Mardones, Bart De Clercq of Belgium - a stage winner at last year's Giro d'Italia - Australian cyclist Leigh Howard and French pair Pierrick Fedrigo and Jean-Christophe Peraud opened up an early lead of five minutes on the main pack.

But the five-man breakaway's lead was trimmed to 1:30 with 40 kilometers (24.8 miles) left, and less than a minute heading into the last two climbs.

A handful of riders crashed in the middle of the peloton with more than 20 kilometers (12.4 miles) to go, but none of them appeared to be hurt.

The front five were caught with Leipheimer's Omega Pharma-Quickstep moving to the front and splitting the chasing pack in two, as many could not keep pace.

They included rider Ivan Basso, who hurt himself on a fall Monday, and reputed sprinter Thor Hushovd. Defending champion Tony Martin also struggled.

Thomas De Gendt surged ahead on his own with 14 kilometers (8.7 miles) left, but the Belgian's effort was shortlived.

Simon Gerrans, who finished second behind Valverde on Tuesday, crashed when a teammate fell taking a bend too quickly and brought Gerrans down with him. The Australian looked dazed but got back up and continued.

Movistar riders forced the pace at the front, thinning the peloton even more, to put Valverde in a great position to attack. But Wiggins had little trouble containing the threat.