Fourteen riders representing twelve teams broke away after . They stayed clear as a group through the four climbs on course before they started to splinter. Danilo Di Luca's LPR team drove the peloton most of the day, because the finish figured to favor Di Luca more than race leader Denis Menchov or the man in third, Levi Leipheimer. However, one team pulling at the front of the peloton proved to be no match for a 14-man breakaway working cohesively, and by the time the peloton reached the descent of the fourth climb, the last before the summit finish, it was clear the breakaway would not be caught. The breakaway was still twelve strong as it began the last climb of the day. Andriy Hryvko was the first to attack for the stage win, but he was caught well before the summit, and wound up finishing in the pink jersey group a minute behind the stage winner. The decisive attack came from Simon Gerrans, who no one could match, giving the Cervélo rider the stage win. Leipheimer and Ivan Basso were both dropped from the pink jersey group just before the summit of the climb and the end of the stage, losing three potentially valuable seconds to the other highly placed riders in the GC. Michael Rogers was a further three seconds back of Leipheimer and Basso, causing him to drop from sixth to seventh in the GC.
