Emanuele Sella powered to a memorable Giro hat-trick on the penultimate stage of this year's race on a day that saw reigning champion Danilo Di Luca's chances of overall glory evaporate into thin air. With just the final time trial left on the agenda, Spain's Alberto Contador is poised for victory.

CFS Group Navigare rider Sella attacked 30 kilometres from the finish on the final climb to Aprica and managed to maintain his lead on the descent to Tirano, finishing 1'04" seconds ahead of compatriot Gilberto Simoni (Diquigiovanni) after almost seven hours in the saddle.

Spaniard Joaquim Rodriguez (Caisse d'Epargne) took third place, 1'21" off the pace, while Italy's Riccardo Ricco (Saunier Duval) pipped pink jersey Alberto Contador (Astana) in a token sprint to take fourth place in the 224km stage 20.

With just four seconds separating Contador and Ricco there is everything left to play for in Sunday's final 28.5km individual time trial in Milan.

But all-rounder Contador, the current Tour de France champion who reacted to each and every attack on Sunday with supreme confidence, will be the favourite to secure his first ever Giro win owing to his superior skills when racing against the clock.

"I will go and preview the course tomorrow," the 25-year-old said. "I want to win the maglia rosa and it would be nice to also win the stage. However, the first objective is the jersey."

The big loser of the day, however, was undoubtedly Di Luca, the 2007 Giro champion who, just 24 hours after resurrecting his chances with an astonishing ride to take second-place in Friday's stage 19, cracked with dramatic effect on the brutal 18% gradient of the first category Mortirelo climb.

Di Luca was riding in the main gruppo containing all the race favourites when his previous day's exploits caught up with him, the Italian being dropped on the Giro's most feared climb after a serious of attacks from compatriot Simoni.

The LPR Brakes team leader lost more than a minute and a half by the time the summit had been crossed, his losses then ballooning during the final 50km of racing.

Riding alongside Russian Vladimir Karpets (Caisse d'Epargne), Di Luca cut a forlorn figure as he crossed the finish line more than five minutes behind stage winner Sella.

Having started the day in third place and just 21 seconds behind Contador, Di Luca relinquished his place on the podium and now sits in seventh, more than four minutes down.

Italy's Marzio Bruseghin (Lampre) moved into third place in the overall standings after he recovered to finish alongside Contador, Ricco, Denis Menchov (Rabobank) and Franco Pellizotti (Liquigas) at the finish.

Two other riders - Belgian Jurgen Van Den Broeck (Lotto) and Italy's Domenico Pozzovivo (CSF) - were awarded the same time at the finish after they took a high-speed tumble with just metres to spare.

But the day belonged to Sella, the diminutive Italian, who only last weekend had secured back-to-back wins in the Dolomites.

Counting his triumphs on three fingers, and smiling to his team car, the race's leading climber broke into tears as he crossed the line to cap what has been an extraordinary three week's racing for the 27-year-old.

"I am without words," Sella said. "Again my team showed well. The emotions are so high for me. I think that today I did something big."

Felix Lowe / Eurosport