Belgian Philippe Gilbert of the Lotto team won the 20th stage of the Tour of Italy over 203km from Naples to Anagni on Saturday.
Russian Denis Menchov held onto the overall lead.
Gilbert sprang away from the bunch in the final 2km on a slight climb and although Frenchman Thomas Voeckler chased him gamely, the Bbox Bouygues Telecom man couldn't quite close the gap.
Former Giro winner Stefano Garzelli led the peloton over the line in third ahead of Australian Allan Davis.
With bonus seconds for the first three finishers, second overall Danilo Di Luca was expected to attack Menchov at the end but he ran out of team-mates to help him in a speedy finish.
And Menchov actually pinched two more seconds on Di Luca in an early bonus sprint so he leads by 20 seconds ahead of Sunday's finale, a 16km time-trial around Rome.
There had been an early eight-man break but they were never allowed much more than a three-minute gap and had been chased down by the time there were 50km still to ride.
That was because Di Luca's LPR team were hoping to spring some time on Menchov at the bonus sprint but it was the Russian Rabobank rider who stole a march on his rival and only the greater raw pace of LPR's Alessandro Petacchi stopped Menchov gaining more time.
Petacchi took the six-second bonus by winning the sprint with Menchov taking four and Di Luca two.
Any hopes LPR had of launching a more successful move on the finish line evaporated as a number of teams without a win in this year's Giro sent riders out of the bunch to attack while others took up the high speed chase.
It all meant that as the line approached Di Luca was isolated and with Menchov marking his wheel he didn't even try to gain the eight bonus seconds for finishing third for fear of giving Menchov a perfect train to launch his own sprint.
Gilbert's attack came at the perfect time and while Voekler initially latched onto his wheel, he couldn't hold the Belgian's pace.
All will now be decided on Sunday with Menchov usually the better time-trialist.
However, the Rome course is a windy, tricky one that favours good bike handlers while there is also a possibility of rain.
Both those factors actually favour Di Luca, the 2007, champion who could yet deliver his legions of fans a grandstand finish.
© 2009 AFP
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