Colombian Miguel Angel Lopez was the most aggressive of the overall contenders as they plunged into the Sierra zone west of Madrid on stage 18 of the Vuelta a España.

When the Astana riders launched their first attack 60km from the finish and the Jumbo-Visma climbing group scattered, it looked like an all-out attack on Roglic was possible, with teammate Omar Freire ahead.

However, a brief attack by Lopez, supported by Jumbo-Visma mountain riders Sepp Kuss and Nielson Powles, allowed Roglic to take the lead on the final climb.

One Slovenian rider proved impossible to beat, but repeated challenges by Lopez allowed him to shake off another rider, Tadej Pogachar (UAE Emirates).

While Lopez moved up to fourth overall, Nairo Quintana (Movistar) became collateral damage in the battle for the white jersey between Lopez and Pogachar. Quintana also lost a minute, dropping from second to third overall behind Movistar teammate Alejandro Valverde.

Valverde later defended his lack of coordination with Lopez and his decision not to switch in the chase group because Quintana was behind him and he did not want to risk the Colombian losing more time.

However, while the Spanish media is excited by the idea that Valverde may still have a chance to win the Vuelta a España, Lopez has proven to be the most aggressive rider at the moment.

"I didn't get any help from my rivals during the attack, but I still managed to get close to the podium today," Lopez said. Lopez added, "I also got back the Best Young Rider jersey, and this is the last year I will be able to win it.

"It was a difficult stage. It's like a jigsaw puzzle for the tactics to work correctly. I didn't have enough of another player in front of me at the break (to support me), but it was difficult to get another player up there."

After leading three times in the first week of the Vuelta, Lopez was less consistent on the climbs in the second week of the Vuelta. In week 3, he missed a breakaway on the flat stage to Guadalajara, and then received a 10-second penalty for taking a handstand from a teammate, dropping him to fifth place.

Lopez insisted that he could still turn things around for a podium finish, and on Thursday's stage he was back in fourth place.

"There are two interesting stages and a lot of terrain left," Lopez claimed. As it stands, Lopez needs a 46-second lead over Quintana to make the Vuelta podium for the second year in a row.

As for the Slovenian, Pogacar was disappointed to lose time, but as he told journalists while warming down behind the winner's podium, "Maybe it was just a bad day."

"Friday will be more relaxed, but Saturday" -- the final mountain stage -- "will be a really difficult day. You never know what will happen there."

"From here to Madrid it will be full gas. But the overall standings aren't that high, so maybe we can spring some surprises."

It would not be the first time in this year's Vuelta a España for him, as he has already won two mountain stages this fall and holds a long lead in the provisional podium and best young rider awards.