The Colombian, riding for Astana, stuck with the favourites in the climb up to the astronomical observatory of Calar Alto before accelerating in the final kilometre to win in front of Froome, whose nearest overall challenger is now Italy's Vincenzo Nibali, riding for Bahrain-Merida.

Esteban Chaves of Orica-Scott dropped down from overall second place after the Colombian lost two minutes.

A group of 14 riders covered 50.9km in the first hour of racing to get away from the bunch but Froome had announced he was aiming for the stage victory and his Sky team-mates drove the peloton to bring the gap down to five minutes.

Orica-Scott upped the tempo for Chaves with 55km to go and quickly brought the gap down to 90 seconds as the front group tackled the Alto de Velefique, 43.5km away from the finish line.

In the course of the climb, Orica-Scott’s Simon Yates accelerated to reach the top with a 90c second lead over the bunch.

In the last climb, Spain's Alberto Contador of Trek-Segafredo and Nibali were the first to attack, 11km away from the summit, and Chaves was swiftly dropped.

Lopez attacked in the last kilometre to solo away to victory.

Froome - seeking to become only the third person to win the Vuelta and Tour de France in the same year - led the chase and only Nibali and Wilco Kelderman were able to follow him as Contador dropped 17 seconds.

Chaves dropped down to third place in the overall classification.

The BMC duo of Nicolas Roche and Tejay Van Garderen dropped out of the top 10 after falling away early in the final climb.

The 72nd edition of the Vuelta, the final Grand Tour of the 2017 cycling season, is due to end on September 10 in Madrid, having started in Nimes on August 19 - the first time the race has ever begun in France.