Versatile Italian Danilo di Luca beat some of the world's best climbers to extend his race lead after a thrilling 15th stage of the Tour of Italy at Auronzo on Sunday.

Italian Riccardo Ricco won the monumental stage in the Dolomite mountains after being prodded over the finish line by his Saunier Duval teammate Leonardo Piepoli.

Both men had been part of a four-man group that attacked Di Luca's group earlier in the race, and they managed to stay at the front unchallenged as the real battle for the pink jersey took place in their wake.

Behind them, Astana's Eddy Mazzeloni had also attacked Di Luca's group, which contained race contenders Gilberto Simoni, Damiano Cunego and Andy Schleck, about 30km from the finish.

At one point the veteran Italian -- named after the legendary Eddy Merckx by his parents -- became the virtual race leader, but Di Luca soon decided to end his fellow Italian's hopes of leading the race.

Having battled their way over three tough mountain passes, it was only a matter of time before one of the climbers in Di Luca's group attacked on the tough climb to the summit of Tre Cime di Lavaredo, some of whose gradients are a punishing 18%.

With less than 10km to the summit finish, Lampre rider Cunego, the 2004 champion, made a less-than-convincing attempt to pull away -- and Di Luca countered almost immediately with relative ease.

Minutes later Di Luca, known as less of a climbing specialist than either Cunego or former two-time Giro winner Simoni, launched a decisive move that brought him a double prize.

After finishing the stage two minutes and 53 seconds behind Ricco, Di Luca saved his pink jersey and stole some more time from Simoni, arguably his biggest rival, who finished 3:20 adrift.

"I showed I was the strongest on the climbs," said Di Luca, who brazenly waited until the steepest parts of the final climb, on the last 4km, to put time on his rivals. "Some people said I wasn't suited to the steep climbs. Because of my speed at pulling away and my cadence, I think exactly the opposite."

Di Luca appears to have taken a giant stride towards a first major Tour triumph -- and he has a rest day to savour on Monday before hitting the mountains again.

The 31-year-old Liquigas cyclist now leads Mazzoleni by 1:51, with the ever-impressive Schleck, of CSC, in third at 2:56. Saunier Duval leader Simoni is fourth at 3:20 off the pace, with Cunego in fifth place.

Ricco, meanwhile, was delighted at claiming a prestigious first victory on what is his debut Giro d'Italia.

"As soon as the first climb, Simoni told us [Ricco and Piepoli] to race ahead and try to win the stage," said Ricco, who started his breakthrough season by winning two stages on the Tirreno-Adriatico earlier this season. "To win the hardest stage on the Giro is just amazing. It's the best day of my life."

After Monday's rest day, the race resumes on Tuesday with a comparatively less difficult stage of 189km from Agordo in the Dolomites to Lienz in Austria.

Simoni will have to pull off an audacious attack there, or on Wednesday's climb to the difficult Monte Zoncolan, if he is to have any chance of loosening Di Luca's grip.

But according to Belgian legend Merckx, the former five-time Giro winner who was present at Sunday's stage, Simoni may already be beaten. "In this Giro, it will be difficult to beat Di Luca." -- Sapa-AFP