La Rabassa - Britain's Simon Yates, of the Mitchelton team, tightened his grip on the Tour of Spain red jersey on Friday after a thrilling 19th stage in the mountains won by Frenchman Thibaut Pinot (Groupama-FDJ).
Yates started the 154.4 km ride from Lleida to Andorra with a lead of 25secs over Movistar leader Alejandro Valverde.
But, as the Spanish veteran struggled to keep pace on the climb to the summit finish of La Rabassa, Yates forged ahead to stretch his advantage to 1min 38sec.
Yates came in 5sec behind Pinot while Dutchman Steven Kruijswijk was 13sec adrift, having been separated from the two frontrunners.
Kruijswijk's strong run means he jumps to third overall, ahead of Spain's Enric Mas in fourth, but still 1:58 back on Yates.
Yates led for 13 days at the Giro d'Italia in May, only to wobble at stage 19, allowing Chris Froome to clinch the pink jersey.
"I really need to be careful," said Yates. "I especially know how it can fall apart in one day. The race isn't finished yet."
A gruelling stage 19 had begun in Catalonia and ended at the top of La Rabassa in Andorra, with 2,618 metres of vertical climbing in between.
The drama, however, was saved for the final ascent when Movistar's Nairo Quintana and Kruijswijk both attacked with 13km left.
Yates, Pinot and Kruijswijk rallied, however, and as Valverde fell away, the trio joined forces to move away from the chasing pack.
Finally, Kruijswijk dropped off, leaving Pinot to dart in front of Yates with 200 metres remaining to claim his second triumph following his win on stage 15.
"It's really the cherry on the cake," Pinot said.
"It was a beautiful stage, fast, with a nice climb. I went on the attack very early and it paid off."
Yates stays on course to become the fifth consecutive British Grand Tour champion after Froome won last year's Tour de France and Tour of Spain, followed by the Giro d'Italia. Geraint Thomas then triumphed at the Tour de France in July.
"It's one of the biggest races we have, really the pinnacle of the sport almost," Yates added.
"But we're not there yet. Tomorrow is a very difficult day and anything can happen so until then, we keep our feet on the ground."
The 'Vuelta' continues with a 97.3km-long stage 20 through Andorra on Sunday, including six classified climbs, ahead of a mainly flat stage to Madrid on Sunday.
Results from the 19th stage of the Tour of Spain, a 154.4km ride from Lleida to La Rabassa on Friday:
1. Thibaut Pinot (FRA) FDJ 3hr 42min 05sec, 2. Simon Yates (GBR/MIT) at 4sec, 3. Steven Kruijswijk (NED/LNL) 13, 4. Rigoberto Uran (COL/EFD) 52, 5. Miguel Angel Lopez (COL/AST) same time, 6. Enric Mas (ESP/QST) s.t., 7. Wilco Kelderman (NED/SUN) 1min 03sec, 8. Alejandro Valverde (ESP/MOV) 1:12, 9. Tony Gallopin (FRA/ALM) 1:15, 10. Nairo Quintana (COL/MOV) 1:49
1. Simon Yates (GBR) Mitchelton 76hr 44min 41sec, 2. Alejandro Valverde (ESP/MOV) at 1min 38sec, 3. Steven Kruijswijk (NED/LNL) 1:58, 4. Enric Mas (ESP/QST) 2:15, 5. Miguel Angel Lopez (COL/AST) 2:29, 6. Nairo Quintana (COL/MOV) 4:01, 7. Thibaut Pinot (FRA/FDJ) 5:22, 8. Rigoberto Uran (COL/EFD) 5:29, 9. Jon Izagirre (ESP/BAH) 6:30, 10. Tony Gallopin (FRA/ALM) 7:21