Irishman Sam Bennett used the 12th stage's intermediate sprint to slightly stretch his advantage over Peter Sagan in the Tour de France points classification, but the former world champion led home the peloton to pick up scraps on the line and cut his deficit in the fight for green to 66 points.
Though his advantage remains considerable after Sagan's relegation for an illegal sprint on Wednesday, Bennett said he cannot get comfortable in green as harder stages loom.
"I knew it was gonna be hard," Bennett said. "We controlled it until the sprint, and I wasn't looking to stay at the front until the end.
"I'm afraid to think about wearing the green jersey in Paris in case it doesn't happen. The situation looks good now, but everything can change so fast here."
The lumpy 218km stage from Chauvigny was the longest of the entire Tour, and came before a return to the mountains today. It was third time lucky for Switzerland's Marc Hirschi as he claimed his maiden Tour de France stage victory in Sarran Correze while Primoz Roglic retained the yellow jersey.
Hirschi, making his Tour debut at the age of 22, had twice been on the podium in the opening week of the race after seeing attacking efforts fall just short of victory, but delivered for Team Sunweb on stage 12 as he broke clear on the climb of the Suc au May before soloing to the line.
It was also Hirschi's his first victory as a professional cyclist, and built on second and third places in the first week of the Tour.
"It's unbelievable," Hirschi said. "Two times I was really close so actually today I never believed I could make it. I can't describe it, it's hard to find the words.
"I had the picture in my mind from the last two stages when I was close. Then in the last three kilometres I believed I could make it. It's my first pro victory and it's in the Tour so it couldn't be better."
Julian Alaphilippe, who pipped Hirschi to the line on stage two in Nice, was part of a large chase group on the descent to the finish.
But the group lacked organisation, with Hirschi's team-mates Soren Kragh Andersen and Nicolas Roche working to shut down attacks, and could not make an impression before a mechanical problem for Alaphilippe ended his own challenge.
"I think if I had tried any harder I would have been disappointed," the Deceuninck-QuickStep rider said. "I tried my best but Hirschi was the strongest man today. I can't really say anything other than I tried my best."
The main group of contenders were content to ride in together to ensure there was no change at the top of the general classification, in which Jumbo-Visma's Roglic leads by 21 seconds from defending champion Egan Bernal of the Ineos Grenadiers.
Those fighting for yellow were therefore hoping for a large breakaway and a relatively stress-free day behind, but for much of the stage that did not materialise with only six riders up the road before the Sac au May changed the shape of the race late on.
"It was maybe not the easiest day," Roglic said. "We expected a breakaway to go from the beginning but the other teams had other ideas. It was not really a rest day, I guess.
"I think it was good warming up for tomorrow. We have to expect a harder stage in the end. Hopefully we can continue riding like this and tomorrow is a new challenge."
Stage 13 will cover 191.5km from Chatel-Guyon to a summit finish on the Puy Mary.
"Tomorrow I believe it'll be a day to make differences, for sure," said Bernal. "It'll be more demanding than today with an explosive finale to finish."