CONTRES, France (AP) Alexander Kristoff of Norway sprinted to victory in the first stage of Paris-Nice on Monday to claim his fifth win this season, while former world champion Tom Boonen retired with a dislocated left shoulder.
The Katusha rider edged Frenchmen Nacer Bouhanni and Bryan Coquard at the end of the 196.5-kilometer (122.1-mile) stage from Saint-Remy-les-Chevreuse to Contres that was marred by Boonen's crash.
''It's my first stage win on the Paris-Nice so it's another step forward because I've tried three times before,'' Kristoff said. ''When we reached the last 700 meters I was the only one left on my team and I managed to get behind the wheel of (John) Degenkolb and Bouhanni, who was in a pretty good position. I knew I had to hold them off, as well as Bryan Coquard, so I didn't know I'd won right away when I crossed the line.''
Michal Kwiatkowski, who won Sunday's prologue, retained the race leader's yellow jersey.
Boonen heavily hit the ground about 17 kilometers (10.6 miles) from the finish after colliding with another rider.
Race organizers announced that the Belgian sprinter suffered a collarbone fracture, while Boonen's team said he underwent tests at a nearby hospital and was diagnosed with ''a left acromioclavicular joint dislocation.''
The one-day classics specialist will be sidelined for a minimum of three to six weeks, meaning that he will likely miss the Tour of Flanders and Paris-Roubaix.
''Unfortunately, because of the injury and the time it takes to recover, Boonen will not be able to participate in the Northern Classics. Tomorrow Tom will undergo further examination in Belgium to diagnose the grade of the dislocation and determine if surgery is necessary,'' Etixx-Quick-Step doctor Yvan van Mol said.
The race continues Tuesday with a 172-kilometer (106.9-mile) trek from the ZooParc de Beauval zoological park to Saint-Amand-Montrond in central France.