Lindsey Vonn withdrew from Sunday's scheduled Alpine Skiing World Cup event in St. Moritz with a back injury, pointing to a singular focus on the Winter Olympics as the reason for her decision.

Vonn suffered an acute spinal joint dysfunction during Saturday's super-G in Switzerland, the American collapsing after the finish line and leaving the venue in obvious pain.

A further super-G and an Alpine Combined slalom event were due to take place on Sunday, only to be cancelled because of fog.

However, Vonn had already not elected to race, opting instead to rest ahead of next week's downhill and super-G at Val d'Isere.

Vonn, a four-time overall World Cup winner and 2010 Olympic downhill gold medallist, posted on Twitter: "Unfortunately I will not be able to race today.

"I am extremely disappointed but my biggest goal this season is the Olympics and I need to take care of myself now so I can be ready for next week, and more importantly, for February. As always, thank you for the well wishes."