Carlos Sastre defied red-hot conditions to make a stunning late surge and claim the 16th stage of the Giro d'Italia.

Sastre, the 2008 Tour de France winner, reeled in Yaroslav Popovych on the final climb to the mountain-top finish at Monte Petrano and claimed his first ever Giro stage win.

The Spaniard crossed the line 25 seconds ahead of pink jersey holder Denis Menchov, who maintained his overall lead of 34 seconds.

The Russian outsprinted Italian duo Danilo Di Luca, his closest rival in the overall classification, and Ivan Basso to clinch second.

Sastre's stage win moved him up to third in the overall standings, but he is two minutes 19 seconds behind Menchov ahead of the Giro's completion next Sunday.

The mountainous 237-kilometre stage from Pergola to Monte Petrano in the Appenines loomed as one of the most significant on the run in to the end of the Giro, with the likes of Di Luca, Basso and Sastre expected to make their move on Menchov.

The tone of the day was set after just two kilometres when a 15-rider escape group attacked away from the peloton, and held their advantage of around six minutes until 100km from the end.

At that point a group of four including Popovych, Francesco Scarponi, Damiano Cunego and Gabriele Bosisio made a further attack, which looked set to pave the way for the Ukrainian to claim the stage.

The stifling conditions, which hovered close to 100 degrees Fahrenheit, got the best of Popovych on the final 10.4km climb to the end, however, and the fast-finishing Sastre profited to claim the win.

Seven-time Tour de France winner Lance Armstrong finished more than three minutes behind Sastre, to improve from 13th to 12th in the overall classification.

Tuesday is a rest day before the tour resumes on Wednesday with another uphill finish in a short 83km stage from Chieti to Blockhaus.