Dutch rider Lieuwe Westra of Team Vacansoleil attacked late in the final climb of the day to win the fifth stage of the Paris-Nice 2012 earlier this afternoon, while Bradley Wiggins of Team Sky extended his overall lead to 10 seconds over his main rival Omega Pharma-QuickStep's Levi Leipheimer.

Wiggins was well positioned at the front of the pack when Frenchman Arnold Jeannesson launched an attack with 700 meters to go. Even though Jeannesson is not a threat for overall victory, Wiggins still chased and isolated himself.

Westra took advantage by surging ahead with a brutal acceleration in the last 300 meters, and Wiggins could not follow him. Westra casually looked over his shoulder and tapped his chest as he crossed the line.

"For the last couple of days I felt super," the 29-year-old Westra said and continued "I have good legs now, and I told myself I should attack today. It's unbelievable to win in front of such big names. It's a great day in my life."

Westra moved into second place, six seconds behind Wiggins, but is also not a major threat to the leader.

"It was a day in hell with the cold air and wind all day. I really must thank (my teammates) Richie (Porte) and Rigoberto (Uran), who did an amazing job," Wiggins said, adding that "it's looking promising" for the Paris-Nice win.

"It's been a good day. It wasn't my kind of climbs, but we've been working on it this winter," the 31-year-old Wiggins said. "My form is the best it's ever been and we continue to work on the things we're weaker at."

Jeannesson, meanwhile, was disappointed to finish seventh.

"Everyone was waiting for Valverde," Jeannesson said. "I'm a bit disappointed because I had the legs to win, or at least to finish third or fourth. Seventh isn't my rightful position," he added.

An early four-man breakaway attacked shortly after the start of the 178.5-kilometer (100.7-mile) mountain stage from Onet-le-Chateau to Mende, which featured three category 1 climbs and ended with a sharp, sinewy ascent up La Croix Neuve.

With nine kilometers (5.6 miles) left, the breakaway group was caught up by the chasing pack, with Alejandro Valverde's Movistar team moving the Spaniard into a strong position for a late attack.

Valverde struggled in the first portion of the final climb up, but Wiggins could not shake him off and Valverde beat the Brit in a sprint to the line to take second place in the stage and shave two seconds off Wiggins' lead.

Valverde moved up to fourth place and is now 18 seconds behind Wiggins, who is also targeting victory at the Tour de France in July. The 38-year-old Leipheimer, who crossed the line in fourth place, remains third overall.

Friday's sixth stage is an undulating trek from Suze-la-Rousse to Sisteron with a few small climbs, but it should not affect the overall order. Saturday's penultimate stage ends with a long category 1 climb, but Sunday's mountain time trial is expected to decide the race winner.

"This was the stage everybody was taking about," Wiggins said and added "But now it all comes down to Sunday."

Wiggins and Leipheimer are evenly matched in time trials, but both have the edge on Valverde.