UAE Team Emirates rider Juan Sebastian Molano sprinted to victory on Stage 12 of the Vuelta a Espana on Thursday. The Colombian took advantage of Kaden Groves' misfortune with the green jersey holder having to settle for second place after getting boxed in and dropping his chain in the final 200 metres. The Australian, who won back-to-back stages in the opening week, indicated he had suffered a mechanical problem. "In the end we got bumped by UAE who came with momentum and my chain actually dropped. I managed to get it on and had a really strong sprint but unfortunately we were too far back and it was too late," Groves, the Alpecin-Deceuninck rider told <i>Eurosport</i>. "I'm super disappointed because it could have been win number three." Molano appeared to catch the Alpecin-Deceuninck riders by surprise and out of position as he surged to the front off the wheel of teammate Rui Oliveira. He would have expected Groves to come back strongly but had enough of a gap to keep the Australian at bay with Boy Van Poppel, of Intermarche-Circus-Wanty, coming third. "Thanks to my team. They were amazing today," Molano said on the last day before the race heads back into the mountains. "I'm very happy to win a stage in the Vuelta last year, now this year. Molano was hit by a car while training in Belgium in March, leaving him concussed and with a broken toe. "After the incident [it was] not easy to return but now it's okay and I'm very happy," he added. Away from Molano's 22nd career victory and UAE Team Emirates' 48th of the season, there was little to write home about during the 150.6km stage. Surprise leader Sepp Kuss will begin Stage 13 with a 26-second advantage over UAE Team Emirates' Marc Soler and one minute and nine seconds ahead of Remco Evenepoel of Soudal Quick-Step. Three-time Vuelta champion Primox Roglic is 1min 32secs back in fourth spot after earning four bonus seconds on the last intermediate sprint. Friday's stage is a key one for general classification contenders, featuring over 4,000 metres of climbing in the Pyrenees on a 135-kilometre run from Formigal to the Col du Tourmalet in France.