The fearsome 13.2 kilometres climb up the Alto de l'Angliru at the close of the 117.5km stage presented Froome with his last major challenge of the race prior to tomorrow’s processional final stage to Madrid.

The Team Sky rider proved up to the task to move to the brink of becoming only the third man in history to win the Tour de France and Vuelta in the same season.

He will be the first for 44 years to achieve the fact. 

France’s Jacques Anquetil and Bernard Hinault achieved the feat in 1963 and 1973 respectively.

Froome was part of a group of general classification contenders who found themselves just over one minute down on a breakaway, which led over the first two climbs.

The small gap had partly been due to Contador’s Trek-Segafredo team, who kept the group close to allow their leader to launch another attack.

Contador began his offensive on the approach to the Angliru when the Spaniard riding past the remaining riders in the breakaway.

The seven-time Grand Tour winner lead by over one minute at six kilometres to go but saw his advantage reduced by Froome and his Dutch team-mate Wout Poels.

Contador, who previously served two-year ban for a failed drug test, held on to conclude his career in impressive style by winning the stage in 3 hours 31min 33sec.

He finished 17 seconds clear of Poels and Froome, the latter being able to begin celebrating having all but secured overall victory.

"It's an absolutely amazing feeling, what a final, Angliru definitely doesn't disappoint," Froome, who will better his runner-up finish from 2011, 2014 and 2016, said.

"It's such a brutal climb.

"We did everything to catch Contador in the final but he was just too strong for us, it's an amazing way for him to finish his career with such a big victory like that, so congratulations to him.

"A massive thank you to my teammates for all the work they have done over the last few weeks.

"It's been an incredible experience.

"Probably one of the hardest Grand Tour I've ridden, if not the hardest."

Having gained 34 seconds on second place Vincenzo Nibali of Italy, Froome now leads his nearest rival by 2:15 heading into the final stage.

Froome and Nibali will be joined on the podium by Russia’s Ilnur Zakarin after he leapfrogged Wilco Kelderman of The Netherlands into third place.

Kelderman, who was dropped on the final climb, will end the race in fifth place with Contador having moved four seconds clear due to his efforts on today’s stage.