Chris Froome extended his overall lead in La Vuelta after Colombian rider Miguel Angel Lopez won the mountainous 129-kilometre 15th stage from Alcala la Real to Sierra Nevada.
Briton Froome still leads Vincenzo Nibali by 59 seconds although the four-times Tour de France winner's stamina will be tested by back-to-back mountain stages over the weekend as he looks to stay in charge of his bid to become the first rider in 39 years to win the Tour and the Vuelta in the same season. "I was really confident. It's awesome. I came in this race with confidence but I never expected something like this".
Earlier in the weekend Rafal Majka (Bora-hansgrohe) took his first-ever Vuelta stage victory, arriving solo at the uphill finish in Sierra de La Pandera, ahead of Lopez and Nibali.
Now second in the mountains classification behind the Italian Davide Villella, Majka entering the last week with ambition.
An exhausted Yates, who is yet to win a stage at a Grand Tour, was caught in the final 4km, nearly coming to a halt as Lopez raced past him. "I was a bit afraid at the beginning - I spent a lot of energy and had to sprint like 100 times just to get in the breakaway", Polish rider Marczynski told reporters after doubling his grand tour stage win tally.
Magnificent Majka climbs to Vuelta stage 14 win as Froome protects lead
The second-place finish gained Froome six bonus seconds and took his overall advantage over his rivals to one minute 19 seconds.
"I'm delighted to have won in Calar Alto and here", said Lopez. I felt good form the beginning, I was climbing easy. "We have seen everything at this Vuelta. crashes, attacks".
There are five more stages after that, with the race due to finish in Madrid next Sunday (September 10).
Race favorite Froome had a mechanical issue with around eight km remaining in the 160.1 km (99 miles) stage from Motril to Antequera Los Dolmones and was forced to change bikes.