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.
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.
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.
Fernando Gaviria inched past Team Sky’s Elia Viviani to prevail in the Tour of Britain’s fourth stage.
Quick-Step Floors star Gaviria won the 165-kilometre stage from Mansfield to Newark but Viviani assumed the overall lead from Caleb Ewan.
Colombia’s Gaviria held off both Viviani and Alexander Kristoff for the victory, in a stage bristling with drama as America’s Brent Bookwalter was forced out of the competition.
Bookwalter crashed into a car parked close to a tight corner and was forced to withdraw from the race, in an incident where several other riders also crashed.
Orica Scott rider Ewan is level on time with Viviani with four stages remaining, but has lost the green jersey with the Italian boasting greater consistency.
Gaviria now sits third but trails by just six seconds.