Frenchman Lafay wins Tour de France second stage
Wout van Aert was second and Tadej Pogacar third in a desperate sprint for the line as English rider Adam Yates retained the overall leader's yellow jersey after the 208.9km rolling run through the Basque Country.
With all eyes on the duel between defending champion Jonas Vingegaard and Pogacar, Lafay gate-crashed the party with a stealth move that caught out everyone and maintained just enough pace to cross the line ahead of his pursuers.
"It's crazy. I was hanging on at times today because that was fast. But I believed all the way and that's what got me over the line," said the 27-year-old.
Pogacar picked up four seconds for coming third at the finish line along the seafront of San Sebastian's scenic horseshoe bay to add to bonuses he collected the day before and in the sprint to the top of day's final climb, the Jaizkibel.
The first real skirmish of the Tour between Pogacar and Vingegaard broke out atop the Jaizkibel.
Vingegaard seemed to have timed a perfect coup as he burst away from the pack, but Pogacar pursued. The Slovenian pipped the Dane at the line to collect eight bonus seconds to the Jumbo man's five.
The battle on the steep 8km climb was fierce, reducing the peloton to around 20 riders.
As they zoomed downhill, rider after rider attempted to escape in a war of nerves that went all the way to the line with fans packed along the roadsides.
With 500 metres to go Lafay made the break and held on to win.with
Adam Yates leads both UAE team-mate Pogacar and the other Yates twin, Simon, by six seconds in the overall standings. Vingegaard is 22 seconds off the pace, or 16 behind Pogacar, who also retained the white jersey as best young rider.
Yates complained that nobody had helped his team UAE Emirates all day, but remained excited.
"This is why I came here (to UAE). We have the yellow and the white and we have to keep it going that way," he said.
"Pogacar brings the level of the whole team up, he's definately great to work with," Yates exclaimed.
The 2019 champion Egan Bernal of Ineos kept pace Sunday and is 43 sec down in the overall standings.
But Australian hope Ben O'Connor lost further ground and is already almost two minutes down.
The 174 remaining riders set off from the Basque capital of Vitoria with haste as an early escape set a blistering pace.
Native-American rider Neilson Powless was a determined and active member of the escape as the Education First rider set about protecting the polka dot climbing jersey with five more of the pine-forested hills on the menu.
He was only caught on the final climb.
"I gave it my all. It's the Tour and I had to. I kept the jersey and that's all that counts," said Powless.
Monday's stage three takes the Tour into France after a 187km run from Amorebieta to Bayonne where a sprint finish is expected between fast men in the peloton.