Sergio Henao showed his class to retain the race lead after a thrilling penultimate stage at the Vuelta al Pais Vasco.

Three ascents of the eye-watering Alto de Aia brought the majority of the peloton to its knees, but a late drive from the Colombian saw him distance the majority of his rivals.

A rousing acceleration for the third stage in succession saw Henao drop pre-race favourite Nairo Quintana (Movistar) before finishing alongside Joaquim Rodriguez (Katusha) at the line.

The pair remain inseparable on the GC heading into Saturday’s decisive time trial, with Brit Simon Yates (Orica-GreenEdge) jumping up to third overall, seven back, after a late attack gained him three seconds at the finish. 2013 race-winner Quintana now sits fourth, 12 seconds adrift.

A sizeable breakaway in excess of 30 riders went clear early on but was whittled down across a savage 155.5km parcours.

Mikel Landa (Astana) proved strongest to take victory in front of a passionate Basque crowd, pushing clear of both Tim Wellens (Lotto Soudal) and Tom Danielson (Cannondale-Garmin) on the final ramp.

With no riders in the break an immediate threat on GC, Team Sky were able to set a measured tempo on the front, with Danny Pate and Xabier Zandio getting through a lot of work before the situation evolved heading into the closing stages.

First time up the Alto de Aia the peloton became stretched and world champion Michal Kwiatkowski (Etixx – Quick-Step) carved out a gap of over 30 seconds on the descent.

That move drew a reaction from behind, with Team Sky, Katusha and Movistar all working together to drag back the Pole, who would ultimately drop time at the finish.

Henao finished seventh on the stage, one position ahead of Rodriguez to maintain his advantage on stage placings going into a technical 18.3km course on Saturday.

"It was a tough stage and we knew it," he told Biciciclismo. "The team has done a great job and then we were joined by Katusha and Movistar.

"It will be decided in the time trial and we all have possibilities. It is open and I will fight until the end. The differences are small. I do not have much time to a quality rider like Nairo.

"Like in 2013 I have the chance to win. I hope my legs respond and anyway I'm happy with what I've done.

After the stage Sports Director Nicolas Portal heaped praise onto Henao, and previewed an intriguing finale.

“The whole team are really proud of him and the riders are fully, fully behind him," said the Frenchman.

“It all comes down to the time trial tomorrow. It’s a really physically hard TT but it’s also very technical. You have lots of tricky descending, which brings up the question whether to use a time trial bike. Even if are less comfortable on a time trial bike you might be able to save some energy and go the same speed as you would be on a road bike. You can get into a good position. But then the last 8km is basically two hard climbs and one descent in the middle.

“If you have a pure climbing bike then it could be an advantage too. So it’s a tricky TT to prepare for and bike choice is really going to be crucial. We’ll talk about it a lot this evening and make a decision.

“We know Quintana is maybe the best guy for a course like this. But we’ve seen that he isn’t on the form he can be. That possibly opens it up for other riders and there are a lot of guys who can be good. Sergio should be able to do a good ride. He’s shown how strong he is in the race. Every time the race has been on he’s been there, at the front, making the pace and attacking. He’s in good form so he will have a chance. But there are lots of guys to watch out for. It should be really exciting.”