CHRIS Froome suffered a setback on his La Vuelta title bid, losing ground to chief rival Vincenzo Nibali as Stefan Denifl handed Aqua Blue Sport their maiden stage victory.

Froome lost 42 seconds on Nibali with his lead on the Sicilian cut to one minute 16 seconds on the gruelling climb to Los Machucos in La Vuelta’s 17th stage.

The Team Sky star was forced onto the defensive and could not stop Nibali cutting his lead, with the Bahrain Merida man finishing fourth.

Britain’s Froome appeared well-set to complete his mission to land the demanding La Vuelta and Tour de France double ahead of yesterday’s action, only to see his sizeable lead hauled back somewhat.

Austria’s Denifl boosted wildcard entrants Aqua Blue Sport with their first stage victory in a contest already beset by controversy for the Irish outfit.

An alleged arson attack destroyed their team bus after the 11th stage of the race, but Denifl put all that to one side to sweep to victory here.

“ I had super, super legs today,” said Denifl. “I waited all La Vuelta for that day.

“I paced myself until today and I went all in. It’s just amazing for the team, for Aqua Blue. It’s our first Grand Tour and we win a stage… I’m over the Moon!

“You always have to believe you’ll win. I just kept on pushing. The climb was perfect for me. There were bits of flat to recover. Now I’ve won a stage at La Vuelta. It’s amazing. It’s the best day of my cycling life.”

Veteran star Alberto Contador powered into second place, trailing Denifl by 28 seconds, to cement fifth place in the overall standings of his final race before retirement.

“I don’t think anyone enjoys gradients over 25 per cent but that’s just how it is and it’s the same for all of us,” said four-time Tour de France champion Froome, 32.

“It’s never nice to lose time but I feel good. Three more days and I’m confident we can get the job done.”

Thursday’s stage 18 is a reasonably flat 169km route from Suances to Santo Toribio de Liebana.