(CNN) -

With the Alps looming large, Norway's Alexander Kristoff took his chance to fulfill a childhood dream and sprint to victory in a stage of the Tour de France Thursday.

The powerfully built Kristoff will be off the pace when the road goes upwards on Friday's 13th stage, but on the less taxing 185.5km run from Bourg-en-Bresse to Saint-Etienne he was in his element in the finishing dash.

The Katusha rider hit the front with a powerful surge and held off green jersey holder Peter Sagan of Slovakia, who again missed out on a stage win despite his consistent high finishes.

The 27-year-old Kristoff has come to the fore this season with a victory in the Milan-San Remo one-day classic but was desperate for a Tour de France stage win.

"I was dreaming about this since I was a child and to finally achieve it is amazing," Kristoff told Eurosport after his victory.

The stage was not totally flat and contained four climbs deemed worthy of classification, enough to end the chances of Kristoff's great rival Marcel Kittel, who has three victories already on the 2014 Tour.

A five-man breakaway was reeled in on the descent of the final climb and after that it was down to the teams with recognized sprinters to get organized for the bunch sprint.

Race leader Vincenzo Nibali retained his two minute 23 second advantage over second-placed Richie Porte of Team Sky, but is aware that the battle for overall honors is reaching a crucial point.

"The Alps will be very tough," said the Italian. "Tomorrow and the next day are really important stages for the Tour de France."

One man missing will be Garmin-Sharp's Andrew Talansky, who rode so heroically to the finish of the 11th stage, despite the effects of heavy falls earlier in the Tour.

He made it inside the time limit, but before the start of Thursday's stage it was announced that the 25-year-old American had pulled out.

"I'm absolutely heartbroken to leave the Tour," he said. "I had hoped the rest day (Tuesday) would allow me time to recover from me injuries."

A team doctor said Talansky was suffering from acute sacroiliitis, a condition which causes acute pain in the buttocks and legs as well as a chest infection.

He joins other major contenders such as reigning champion Chris Froome and two-time winner Alberto Contador on the sidelines, all victims of crashes.