The first three stages of the 2011 Tour Down Under belonged to the sprinters. The fourth stage belonged to Cameron Meyer.

The multiple world champion seized the overall lead in the season's first race Friday, surviving an audacious breakaway about 20 miles into the 76-mile stage from Norwood to Strathalbyn. Meyer then sprinted away from his nearest challengers to the finish line.

"It's a little bit of a shock I guess, to pull off a stage in the Tour. It's obviously renowned for the sprinters and they've had control of the race so far," Meyer said. "Our plan today was to put a couple in the break. We had the strength to hold it off."

The rider for U.S.-based Team Garmin-Cervelo held off Dutch riders Thomas De Gendt and Laurens Ten Dam to break the stranglehold on the race held by the sprinters, providing its fourth overall leader in as many stages. Meyer has a time of 12 hours, 54 minutes, 30 seconds to lead the overall race by 10 seconds over Ten Dam another two seconds over Matthew Goss.

Seven-time Tour de France winner Lance Armstrong came in 85th of 131 riders, 41 seconds behind Meyer, and was officially 81st overall after four stages. He is 3 minutes, 56 seconds down on the race leader in his last professional race outside the United States.

Afterward, Armstrong suggested on Twitter that the U.S. Anti-Doping Agency is investigating some of the claims raised by a report in Sports Illustrated this week connecting him to doping.

"Great to hear that USADA is investigating some of SI's claims. I look forward to being vindicated," Armstrong tweeted to his roughly 2.7 million followers.

Armstrong has refused to comment on the Sports Illustrated report and did not speak to reporters after the fourth stage. Attempts to reach him later in the evening were unsuccessful.

British sprint star Mark Cavendish, a winner of 15 stages on the Tour de France, lost a full minute to the race lead Friday. He finished 98th two days after sustaining numerous injuries in a crash, and is 17 minutes, 20 seconds off the lead.

Meyer began the stage in 46th place, 21 seconds behind Goss, but transformed the race's overall standings with bold tactical riding and effective co-operation among the breakaway group, which included his compatriot and Garmin teammate Matthew Wilson.

Goss finished at the head of a peleton that was 24 seconds behind Meyer, who won gold medals in the madison, points race and team pursuit at last year's track world championships.

Ten Dam of the Rabobank team improved from 40th place overall, pushing back Goss to third, Robbie McEwen of Armstrong's RadioShack team to fourth, and German defending champion Andre Greipel to fifth, 16 seconds behind the overall leader.

Meyer praised the hard work and co-operation of the leading group for his first stage victory in the Tour Down Under, the first event of the 2011 WorldTour season.

The group went to the lead about a third of the way into the stage, after riders snaked their way out of Adelaide up the steep and heavily-wooded Gorges road and into rolling hills southeast of the city. McEwen won the first intermediate sprint to secure time bonuses which lifted him into second place overall behind Goss and ahead of Greipel.

Then came the breakaway and the complexion of the stage and race changed dramatically.

The group never led by more than 2½ minutes, but kept a reasonable margin over the chasing peleton until the final mile, when the bunch at full pace couldn't close the gap.

McEwen was among the sprinters who expected the peleton to work together to reel in the breakaway and set up the finish down the long main street of Strathalbyn. He said a lack of organization and co-operation among the bunch meant the breakaway could not be caught.

"The race is still not lost," he said. "It's never over, but realistically the sprinters need to take some seconds tomorrow to set it up for (the final stage) on Sunday.

"We (the RadioShack team) took our responsibilities in the peleton. We should probably have had it more under control, but we needed other teams to come up and do their share."