(Reuters) – Tomasz Marczynski picked up a second stage win on this season’s Vuelta A Espana by coasting to victory in stage 12 on Thursday with a gap of 52 seconds, while Chris Froome saw his overall lead reduced by 20 seconds after enduring a hapless finale.

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. Moments later he crashed into a bend, coming over the finish line 52 seconds behind Alberto Contador, who finished strongest of the general classification group.

The Briton lost 20 seconds on nearest challenger Vincenzo Nibali, but still holds onto the red jersey with a lead of 59 seconds over the Italian, who will look to take advantage of having fresher legs than the Tour de France holder in the final week of La Vuelta after sitting out the Tour.

Contador, who will retire after La Vuelta, continued to show he is not ready to bow out quietly and attacked from the peloton with 20 km to go alongside Nicolas Roche and opened up a 10 second lead, eventually finishing 22 seconds ahead of Miguel Angel Lopez, who had won stage 11 the day previously.

“It was an incredible stage. After my first victory I was keeping fresh to try again today. 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.

“Once I was there I said ‘today can be again my day’. I felt good form the beginning, I was climbing easy. I kept calm until the last climb and there I wanted to see how the others were doing, and when I saw I had good legs I tried to go alone.”