Mark Cavendish

Mark Cavendish, left, edges ahead of John Degenkolb to win the first stage of the 2014 Amgen Tour of California on Sunday in Sacramento. (Ezra Shaw / Getty Images / May 11, 2014)

The first stage of the Tour of California ended with the closest finish in the race's history, with the winner decided by a tire's width.

Even winner Mark Cavendish didn't know the result after crossing the finish line at the State Capitol in Sacramento.

"I really had no idea who had won," the British cyclist told NBC Sports Network after the race. "I had to wait a little bit until they confirmed. I really had no idea."

After almost five hours of racing on Sunday, Cavendish took the yellow jersey, edging out John Degenkolb of Germany in an outcome that had to be confirmed by video replay. Cavendish also edged out Dutch rider Moreno Hofland who finished third, and Slovakian Peter Sagan, who Cavendish passed on his push to the finish.

Early in the race, a breakaway formed with Matt Cooke, Charles Planet, Thomas Leezer, Isaac Bolivar, Will Routley and Tao Geoghegan Hart, who, at 19, is the younger rider on the tour. The break stayed away for much of the race and at once point held a lead as large as five minutes.

But near the end of the course the rest of the field closed in, allowing sprinters like Cavendish, Sagan and Kiel Reijnen to make their way to the front for a dramatic finish.

Gusty conditions complicated the 120-mile stage — the longest of this year's tour — with winds reaching more than 20 miles per hour.

Routley became the first owner of the King of the Mountain jersey, edging out Cooke during the climb up Highway 49 halfway through the race.

American Carmen Small won the 125-mile women's circuit race, winning a purse of $10,000.

The ninth Tour of California will continue Monday in Folsom with a 12.5-mile individual time trial on a flat course.

james.barragan@latimes.com