Acevedo, riding for Jamis-Hagens Berman, completed the 102.9-mile stage from Breckenridge to Beaver Creek in heavy rain in 4 hours, 9 minutes, 8 seconds.

Van Garderen, the American BMC rider who began the day in fourth place, conceded the stage win to the Colombian but was given the same finishing time.

"I felt good today and I was confident," said Acevedo, who also won a mountaintop finish stage in May at the Tour of California. "I had good legs."

Van Garderen took a 4-second lead over teammate Mathias Frank of Switzerland. Frank finished third in the stage, 13 seconds behind.

Acevedo, who began the day in 13th place, moved to third overall - 30 seconds back.

"Garmin was trying to make it hard and they did a good job; they dwindled the field to nothing," said van Garderen, who finished third and second in the previous two USA Pro Challenge editions. "But I think they underestimated me and my teammates a little bit."

Van Garderen, Acevedo and Tom Danielson (Garmin-Sharp) crested the steepest climb of the day with 7.4-mile left before a steep several-mile descent and a steep mile climb to the ski resort finish.

Danielson - fourth overall, 40 seconds back - fell off the pace quickly and the top-two finishers rode together to the finish in hard rain.

"It was wet and tricky and Danielson looked a little timid," said van Garderen, the Tour of California winner. "And so I said, 'OK, let's go for it.' And we were able to get a little bit of a gap."

Van Garderen and Acevedo pedaled to the finish without attacks.

"My goal was to distance myself from Danileson," said van Garderen, who finished fifth in the 2012 Tour de France but placed 45th this year in cycling's biggest race. "Acevedo's goal was for the stage so we worked together well to accommodate each other's goals."

Previous race leader Lachlan Morton (Garmin-Sharp) of Australia paced teammate Danielson early in the final climb, then fell back and conceded his two-day tenure as the race leader.

Morton, who finished eighth in the stage, dropped to fifth overall - 1:17 behind.

The weeklong race continues Friday with the 10-mile individual time trial. The field will contest the uphill route individually in reverse of the overall standings.

The event will end Sunday with the 72.4-mile Denver Circuit Race.