BRECKENRIDGE - In arguably the toughest stage in the three-year history of the USA Pro Challenge, the field of elite international cyclists splintered like never before Tuesday afternoon.

Boulder resident Lachlan Morton of Garmin-Sharp took over the yellow jersey as overall leader with a stellar performance on the climbs.

The day started with a steep ascent of Independence Pass, but the race really got going with multiple attacks on Hoosier Pass. Once the riders reached Breckenridge, the time gaps only widened during a short, very steep climb through town.

The seven-day race continues Wednesday with a route from Breckenridge to Steamboat Springs. It concludes Sunday in Denver.