The peloton crosses a bridge over the Russian River during Stage 1 of the Tour of California cycling race on Sunday, May 13, 2012, in Monte Rio, Calif. (AP Photo/Marcio Jose Sanchez)

SANTA ROSA, California, May 13 (Reuters) – Peter Sagan overcame a flat tire in the final 10 kilometers (seven miles) to win the opening stage of the Tour of California in a sprint finish on Sunday.

The Slovakian, one of the most promising riders in professional cycling, further enhanced his growing reputation when he won the 186 kilometer (116 mile) stage, that started and finished in Santa Rosa.

The 22-year-old got back in the saddle after changing his rear wheels and timed his run to perfection to win the stage by about two bike lengths, in a time of four hours, 42 minutes 36 seconds.

“It was a really confusing sprint because it was a small field,” said Sagan, a former junior world mountain cyclist who turned to road cycling in 2008.

“With 10 kilometers to go I flatted, but I knew there was time to get back in.

“Thanks to the work of my teammates I didn’t panic, and we were able to get back on easily.”

Australian Heinrich Haussler finished second in the opening stage while American Fred Rodriguez crossed the line third, both in the same time as Sagan.

Sagan lost around 25 seconds to the field while mechanics changed his rear wheel but two of Sagan’s teammates towed him back to the main field in quick order.

It was Sagan’s fourth stage win at the Tour of California, the most prestigious cycling event in the United States, and the 27th overall of his professional career, but he did not expect to win the eight-day Tour.

“It is going to be very hard to hold onto the yellow jersey,” said Sagan.

“I’m okay on the smaller climbs, but it’s only going to get harder and harder as the week goes on.”

Tom Boonen of Belgium, the world’s number one ranked road cyclist, suffered a puncture just before the spring to the line and was unable to make an impact.

As the pace increased before the sprint to the line, several riders crashed near the front of the peloton. Last year’s winner, American Chris Horner, survived unscathed and finished in the middle of the pack.

The opening stage came to life early. Eight riders broke from the field of 128 just after the neutralized start.

Almost halfway through the stage, they led by more than 11 minutes, but were swallowed up by the chasing pack after four and a half hours of hard pedalling.

The Tour continues Monday with a 189km (117 miles) stage from San Francisco to Aptos.