Defending champion Levi Leipheimer opened a 9-second lead Saturday in the USA Pro Challenge overall standings, while Australia's Rory Sutherland won the uphill sixth stage.
Leipheimer, the Omega Pharma-Quickstep rider based in Santa Rosa, Calif., began the day in fourth place - 8 seconds back. He was fourth in the stage, 26 seconds behind Sutherland.
"I can't take credit for planning it like that, but obviously it was in the back of my mind to do that," said Leipheimer, who won three multi-day races in 2011 but has ridden through an injury-riddled season, including fracturing a fibia in a training accident in Spain on April 1. "The guys (teammates) have gone above and beyond what they could do this week. We were down a lot of guys, but this is for them. I'm very happy."
The second-year race will end Sunday with a 9.5-mile time trial in Denver.
Sutherland, who competes for U.S.-based UnitedHealthcare, completed the 102.8-mile stage from Golden, the last mountain stage of the weeklong race, in 4 hours, 6 minutes, 12 seconds for his second win of the season.
Former race leader Christian Vande Velde of Garmin-Sharp and Lemont, Ill., dropped to second overall.
Sutherland, who has lived in Boulder for several years, emerged from a lead group with about three miles left and at the base of the final climb. He rode alone for the rest of the stage.
"I know this climb well enough that I knew I had to go at the bottom," Sutherland said. "I know where to go easy, I know where to go hard. I've done this climb, I don't know how many times. But this was the most beautiful one I've done."
Tejay van Garderen, the Garmin-Sharp rider from Bozeman, Mont., who has twice led the race via tiebreaker, faded in the waning miles and finished 11th. Van Garderen was third overall, trailing Leipheimer by 21 seconds.
"It's possible. It's going to take an incredible ride," van Garderen said. "But I can still win this race." Fabio Aru of Italy was second in the stage, 20 seconds behind Sutherland.