Chris Froome extends overall Vuelta a Espana lead after gruelling Sierra de la Pandera mountain stage

Stage 15 report: Vincenzo Nibali attacks with 13 km to go and opens up 20-second gap with Froome's group - but Italian could not keep it up

Chris Froome could become the first rider in 39 years to win the Tour de France and La Vuelta in the same season (AFP/Getty Images)

Chris Froome increased his overall lead in the Vuelta a Espana to 61 seconds on Sunday, edging himself closer to securing a maiden red jersey.

The Briton came fifth in stage 15’s punishing Sierra Nevada mountain route on Sunday 47 seconds behind Colombian winner Miguel Angel Lopez.

Froome crossed the line six seconds ahead of Vincenzo Nibali, his nearest challenger in the general classification, who finished seventh.

Russian Ilnur Zakarin placed second, 36 seconds behind Lopez, to move up to third overall.

Monday is the second rest day of the race, which continues on Tuesday with the individual time trial, where Froome will be looking to strike another blow in his bid to become the first rider in 39 years to win the Tour de France and La Vuelta in the same season.

The stage, which finished at the Sierra Nevada ski station, featured two first category and one 'outside category' climbs in the final 70 kilometres.

The Sierra Nevada is commonly used by riders for altitude training, which added another layer of difficulty to the stage, and Froome had said he had been saving himself in Saturday's climb up La Pandera for Sunday's gruelling circuit.

Froome had awful memories of last year's Vuelta stage 15, when Alberto Contador and eventual winner Nairo Quintana attacked from the starting gun, leaving the Briton isolated from his team and wrecking his bid to win the overall race.

Froome and his Sky team mates were determined not to make the same mistakes again and on Sunday kept check on Nibali's movements.

Nibali, who did not compete in this year's Tour de France, waited his turn to attack while Alberto Contador, Romain Bardet and Lopez formed a group ahead of Froome's bunch.

The Italian finally made his move with 13 km to go and opened up a 20-second gap with Froome's group but could not keep it up and was soon caught, thus weakening his chances of grabbing the leader's red jersey from the Briton with six stages to go.