Madrid - Ireland's Sam Bennett launched a sudden attack in the direct aftermath of a mass fall on the home straight on Saturday to win Stage 14 of the Vuelta a Espana at Oviedo.
Overall Vuelta leader Slovenia's Primoz Roglic missed the crash but was slowed down by it and remains 2:25 in the lead with two monster mountain stages on Sunday and Monday.
World champion and second placed Alejandro Valverde and third placed Tadej Pogacar ended up with cuts and bruises in the crash in a dramatic culmination of what had been expected to be a straight bunch sprint.
"I knew they'd be going full gas, I was lucky to avoid it," said an exhausted looking Roglic.
After winning the first flat stage in Valencia last week Irish champion Bennett set off after Max Richeze of Deceuninck-Quick Step and Tosh Van der Sande of Lotto Soudal as they suddenly found themselves advancing toward the line, with Bennett burning them off with ease.
He raised one finger in a tentative celebration at the line and later said he was asking if he had won.
"Because I wasn't expecting to be in the mix I wasn't concentrating and didn't know if the breakaway had been caught or made it home," Bennett said.
"I just kind of found myself in a small group after the crash and bided my time because they were going too fast."
"At 300m I went for it because I just wanted to get it over," Bennett said.
In bright sunshine with a clement 21 degrees Celsius the peloton had embarked on the third of six flat stages (out of 21) from Vicente de la Barquera and wound through a series of picturesque seaside towns and the lush rolling countryside of the Asturias region.
With the Bay of Biscay and the Cantabrian mountains providing a spectacular backdrop a small breakaway got a slight lead and clung on until the outskirt of Oviedo.
A slight narrowing of the road appeared to be the cause of the crash just as the sprinters began to jostle for position and a shoulder charge from one rider sent a ripple of panic across the peloton just as it was hitting top speed 1km from the line.
Roglic, who seized control of the overall Vuelta lead by pulverising his rivals on the individual time-trial in midweek, further demoralised other pretenders Friday by thriving on the 'hors categorie' ascent to Los Machucos summit finish.
The former ski-jump champion, who came third in the Giro d'Italia after all his rivals ganged up against him, leads by a weighty 2:25 from Valverde.
Pogacar is at 3:01, Miguel Angel Lopez is fourth at 3:37 and Nairo Quintana fifth at 5:21. Each will be considering a move to reduce that deficit over the next two days.
Sunday and Monday will provide a deep test of Roglic's resolve as the true climbers can test the Slovenian's stamina before Tuesday's rest day and the final week of racing.