Francesco Mancebo of Rock Racing, along with Liquigas’s Vincenzo Nibali and QuickStep’s Jurgen van de Walle turned the Tour of California upside down Sunday in a stunning first stage.

Mancebo attacked from the start of the 107-mile stage from Davis to Santa Rosa, powered away from a couple of breakaway partners with about 45 miles to go, then outlasted Nibali and van de Walle, who bridged up from the elite chasing group to challenge Mancebo on the final finishing circuit.

In doing so, Mancebo, Nibali and van de Walle finished nearly 2 minutes ahead of the chasing group, which included two-time defending champion Levi Leipheimer and Astana teammates Lance Armstrong, Chechu Rubiera and Chris Horner.

The Astana boys helped trim Mancebo’s lead to one minute at one point and appeared to be primed to overtake him before the finishing line and put Leipheimer in yellow. But they called off the chase  and let Nibali and van de Walle get away from their group on the first of three circuits in Santa Rosa.

With a deficit of almost 2 minutes, Leipheimer and Astana may be hard pressed to make up time on Mancebo and especially Nibali over the next eight stages. Mancebo’s a mountain goat, tho Rock may be hard-pressed to defend with a far weaker team than Astana, Columbia-High Road, Garmin-Slipstream and Saxo Bank. Nibali may be the biggest threat to Leipheimer’s overall, as he’s a good time trialist. At last year’s Tour of Missouri, he finished the 18-mile TT in Branson in sixth place in 41 minutes 6 seconds, 1:15 behind winner Christian VandeVelde and 1:29 behind Leipheimer’s winning time from the 2007 ToM.

Astana likely didn’t want to get Leipheimer into yellow too early and defend for the rest of the race, but in letting Nibali escape, they may have let him get too far ahead and hurt Leipheimer’s chances for the overall.

Or not. Columbia-High Road’s Michael Rogers and Garmin-Slipstream’s David Zabriskie and the Schleck boys of Saxo Bank rode with Astana in the chase group so they’re in the same boat as Leipheimer, giving their teams impetus to work with Astana to bring time back from Mancebo and Nibali.

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