Tom Dumoulin moved closer to the Vuelta a Espana title by increasing his lead in the red jersey to six seconds on Friday's stage 19.
France's Alexis Gougeard of the Ag2r la Mondiale team won the 185.8km stage from Medina del Campo to Avila, but the day's biggest winner was Dutchman Dumoulin.
The Giant-Alpecin's rider finished in 25th place, 16 minutes 18 seconds behind Gougeard, but three places and three seconds clear of Fabio Aru (Astana).
Italian Aru is Dumoulin's nearest rival in the general classification and now sits six seconds behind. Joaquim Rodriguez (Katusha) is a further 1min 21secs adrift.
Saturday's mountainous 175.8km 20th stage could be the final chance for Aru to wrestle the red jersey from Dumoulin's shoulders as Sunday's finale to Madrid is likely to be settled by the sprinters.
It is 35 years since a Dutchman won a Grand Tour, when the legendary Joop Zoetemelk won the 1980 Tour de France. He also won the 1979 Vuelta.
Ireland’s Nicholas Roche, who won Thursday’s 18th stage, remains in 27th place overall, nearly 48 minutes behind the race leader.
"I attacked to try to win a few more seconds," Dumoulin, who along with Aru was involved in a minor crash earlier in the stage, told reporters.
"I am feeling very good," he added. "I was under stress because everyone wanted to attack me but I dealt with it well.
"Tomorrow will be an exciting day when a lot of things could happen. My strategy will be to follow Aru and I will have to see with the team directors if there is any more we can do.
"But my team is better than many people think and I hope they can show that."
