American Levi Leipheimer assumed the overall lead in the Tour of California with a second-place finish in the race's most difficult stage.

Robert Gesink, a second-year professional from the Netherlands, won the mountainous 165-kilometre road stage from Modesto to San Jose in four hours, 28 minutes, 29 seconds.

Leipheimer, the defending champion and third-place finisher in last year's Tour de France, finished just behind Gesink in the same time having completed the five categorised climbs, which included the ascent of Mt. Hamilton.

Jurgen Vanderwalle of Belgium was third in the stage, leading a pack of 14 riders, 19 seconds behind.

Leipheimer started in sixth place, trailing former race leader Tyler Farrar of the US by seven seconds.

He now has a 13-second cushion over former race leader Fabian Cancellara (CSC) of Switzerland.

Gesink is third overall, trailing by 15 seconds, with four stages of the 1,072-kilometre, eight-day race remaining.

Farrar, who held a one-second race lead over Cancellara entering the stage, withdrew after about two and a half hours of the third stage with a stomach virus.

Reuters