Alejandro Valverde insists "the dream remains alive" as he bids to overhaul Primoz Roglic to clinch the red jersey in La Vuelta.

Ten years after his first and only triumph so far at his home Grand Tour, veteran Valverde is bidding to thrill the Spanish crowds with another title.

He sits second heading into the final five days of the tour, which finishes in Madrid on Sunday.

Tuesday was a rest day, a chance for reflection on the first 16 stages of the race and to look forward to the remaining challenges.

Slovenian Roglic is in La Roja jersey and the Jumbo-Visma rider holds a lead of two minutes and 48 seconds over second-placed Valverde.

At the age of 39, reigning road world champion Valverde is 10 years Roglic's senior, and his experience could yet prove significant in the race to the capital.

"I don't stop surprising myself," said Valverde. "I'm 39 and I feel like I was on my second Vuelta, in 2003, when I fought for the podium and finished third.

"I keep fighting, I keep attacking, sometimes I gain time, sometimes I lose it, but the dream remains alive. People support me a lot and I thank everyone for their love."

Valverde lost 23 seconds to Roglic on Monday but the Movistar man is sure there could still be twists to come, heading into Wednesday's 219.6-kilometre stage 17 from Aranda de Duero to Guadalajara.

"There's still time for anything to happen: for the leader to fade, for us to lose time or us to recover. The third week can take its toll on anyone," Valverde said in a team news conference on Tuesday.

"We are realistic: Roglic is very, very good. But we have also seen him fail sometimes.

"We have to try. If the day comes when we have to just fight for the podium, then will be the time to think about that. My record is very good, especially in La Vuelta, but a podium would be a good result if we can't fight for the win."