Pomarance - Zdenek Stybar timed his attack to perfection to win the second stage of the Tirreno-Adriatico and move into the overall lead on Thursday.
The Czech rider went clear at the top of the tricky final climb, opening up a gap on the short descent and holding off the chasing pack to win the 207-kilometre stage from Camaiore to Pomarance.
Peter Sagan of Slovakia was second, leading home an elite group of chasers finishing a second behind Stybar. Edvald Boasson Hagen of Norway was third.
"We planned it a little bit two and a half weeks ago with (Etixx-Quick-Step sport director Davide) Bramati that this could be a stage for me. So I was pretty focused for this stage," Stybar said.
"I knew that the last two or three kilometres were very technical, which is good for me. I tried to go. I didn't really plan to go there but I saw the opportunity, the space, and I thought 'OK, the bunch will slow and I'll go with everything I have.'"
Local favourite Diego Ulissi attacked on the slopes of Il Cerreto, which had gradients of more than 16 percent, but he was reeled in and passed by Stybar near the summit.
Vincenzo Nibali gave chase in the final kilometre but was unable to bridge the gap and the Italian was swallowed up by the peloton in the sprint to the line.
American squad BMC Racing won the opening team trial stage on Wednesday to put Daniel Oss into the leader's blue jersey but the 10-second stage winner's time bonus saw Stybar take over the overall lead.
The Etixx-Quick-Step rider has an advantage of nine seconds over Oss' teammates, Greg Van Avermaet and Tejay van Garderen.
The seven-day Tirreno-Adriatico continues on Friday with a 176-kilometre ride from Castelnuovo Val di Cecina to Montalto di Castro.