Simon Yates has just one more mountain stage to conquer in his bid for La Vuelta glory after stretching his lead by more than a minute with a commanding ride on stage 19.
Bury rider Yates finished second to Frenchman Thibaut Pinot on top of the Coll de la Rabassa in Andorra but managed to extend the distance to his main rival Alejandro Valverde and increase his advantage ahead of Saturday's decisive stage 20 to a summit finish on the Coll de la Gallina in Santuario de Canolich.
The provisional general classification showed Yates with a lead of one minute 38 seconds over Movistar's Valverde, with LottoNL-Jumbo's Steven Kruijswijk in third place, a further 20 seconds back.
Yates is attempting to secure his first Grand Tour victory and what would be a fifth consecutive Grand Tour win for a British rider.
It was a second stage win for Groupama-FDJ's Pinot following his success on stage 15, but the focus was on the battle between Yates and Valverde.
Movistar made the first move, sending Nairo Quintana up the road early on the 17km final climb to try to tempt Yates out. Kruijswijk and his team-mate George Bennett quickly responded but Yates initially sat in.
Pinot began to bridge over with 11km left but when Yates made his move with 10km remaining, Valverde had no answer.
Quintana dropped back for his team-mate but their chase began to fall apart when the Colombian suffered a puncture, while Yates continued to drive the pace at the front.
The gap quickly grew and it was clear Valverde had no response as the likes of Wilco Kelderman and then Rigoberto Uran left him behind.
Yates was happy to let Pinot take stage honours, knowing he has put himself in position to effectively secure victory on Saturday before Sunday's processional stage into Madrid.