Isaac Del Toro took the overall lead at the UAE Tour after darting clear to earn his second stage victory of the week atop the Jebel Hafeet mountain on Saturday.
The 23-year-old Mexican started the day 21 seconds behind Italian Antonio Tiberi, who had claimed the overall lead with victory on Wednesday's queen stage.
But he could not live with the UAE team star Del Toro, who dropped his Italian rival with 2.5-kilometres to race of stage six after Tiberi had initially matched a previous acceleration 4km from the finish.
"If one time it doesn't work, you still need to have it in your head that you're able to do it," Del Toro said of those attacks.
"I think today is one of the top three victories in my career," added Del Toro, who was a revelation last year when he finished second at the Giro d'Italia.
Tiberi could finish only fourth, 31 seconds back at the end of the 168km stage from Al Ain Museum, with Australian Luke Plapp taking second at 12sec and Austria's Felix Gall third at 21sec.
It leaves Del Toro 20sec clear of Tiberi and more than a minute ahead of Plapp ahead of Sunday's final stage, which is not expected to result in any major changes as it is one which suits the sprinters.
Olympic champion Remco Evenepoel had another tough day in the saddle, finishing the stage in 15th place, almost a minute back, leaving him 10th overall at 2min 25sec.