Astana's Dario Cataldo won the 15th stage of the Giro d'Italia on Sunday outsprinting the other survivor of a long breakaway, fellow Italian, Mattia Cattaneo in Como.
Richard Carapaz, the overall leader, finished 11 seconds behind with Simon Yates and Vincenzo Nibali, but Primoz Roglic, who came off his bike on the final descent, lost 40 seconds to the Ecuadorean.
While Cataldo and Cattaneo of Androni played cat and mouse up the final straight for the stage victory, the heavyweight contenders were fighting a desperate battle for seconds behind them at the end of the 232-kilometre stage.
Nibali of Bahrain Merida attacked throughout the closing stages and only Carapaz and two Britons, Yates, of Mitchelton Scott, and Hugh Carthy of Education First, managed to stay with the Italian. They finished just 11 seconds behind Cataldo. Yates snatched third to pick up a four-second bonus.
"I wanted to see how the others responded," Nibali said at the finish adding he was happy he was "able to do something."
Carapaz increased his lead to 47 seconds over Roglic. Nibali is another minute further back in third.
"Among those in contention for the victory, there is also Carapaz," the Ecuadorian said but accepted Nibali had taken the initiative on the stage. "It was a mistake, on my part and on Roglic's part, to give him so much space."
The Movistar rider said Nibali was a threat.
"I think he's very strong," Carapaz said. "I think I'm going to be seeing a lot of him this week. We both want to finish on the podium, so it should be quite a spectacle for the people watching on the TV."
- 'Champion's mindset' -
Nibali was greeted at the finish by the 36-year-old Alberto Contador, winner of seven Grand Tours.
"I told him that he has always been an inspiration," said the 34 year-old Sicilian, who has won four major tours. "He could attack unexpectedly, up or down, in a key stage or on a transitional stage."
"He didn't want to be second or third, he was just riding to win. That's a champion's mindset."
Spaniard Mikel Landa, Movistar's team leader, was part of a quintet that finished 36 seconds behind the winners.
Slovenian Roglic, who started the day seven seconds behind Carapaz, rode into a barrier taking a corner too wide as the contenders took terrifying risks on the final descent. He had to exchange bikes with a team mate and came in 51 seconds behind the winner in a trio that also contained Trek-Segafredo's Dutchman Bauke Mollema.
Nibali said Tour of Spain champion Yates had demonstrated better form.
"He is more than five minutes away," Nibali said, "but he has shown that his condition is improving."