VITTEL, France — One day Peter Sagan was twirling his fingers and celebrating victory.
A day later, the world champion from Slovakia — one of the sport's biggest stars — was disqualified from the Tour de France.
Sagan was sent home Tuesday for causing a serious crash in a chaotic sprint finish that left Mark Cavendish needing treatment for his injuries and further examinations in a hospital.
About 50 meters (yards) from the end of Stage 4, Sagan elbowed Cavendish, who was squeezed against the barriers to his right, out of the way.
Cavendish slammed into the barriers and two other riders plowed over the British sprint specialist, a winner of 30 Tour stages.
"We have decided to disqualify Peter Sagan from the 2017 Tour de France after the tumultuous sprint here in Vittel, where he endangered several riders, including Mark Cavendish and others who were involved in the crash," race jury president Philippe Marien of the UCI said.
Marien said they were applying UCI race rules that allow them to disqualify riders in "serious cases."
Cavendish was taken to hospital with hand and shoulder injuries.
"I will definitely need stitches in this finger, it's bleeding a lot," he said. "With the shoulder, it might be something to do with a previous injury, it's sat backwards so I'm not sure if I've done something to the ligament.
"I'm not a doctor, but from the feelings I'm not optimistic."
Apart from doping offenses, disqualifications are rare in the Tour. In 2010, Australian Mark Renshaw was thrown out for a head-butt that cleared a path in a sprint for his teammate Cavendish to win the stage in Bourg-Les-Valence.
"If there was a mistake, then you have to congratulate the jury for having the courage to punish the world champion, the big star of cycling today," said France's Arnaud Demare, who won Tuesday's stage.
Sagan was aiming to match Erik Zabel's record of six green jerseys in the Tour's points classification, and he was right on target after winning Stage 3.
"I get on with Peter well, but I don't get ... if he came across is one thing, but the elbow. I'm not a fan of him putting his elbow in me like that," Cavendish said.
"A crash is a crash, I'd just like to know about the elbow, really," Cavendish added. "I'd just like to speak to him about it."
After the crash, Sagan went over to see how Cavendish was and patted him on the back, while the British rider showed him his wounds.
The Slovak, who had won Stage 3, said later he had apologized to Cavendish.
"It's not nice to crash like that," said Sagan, who had finished the stage in second place behind Demare.
"It's the sprint. I just didn't know that Mark is behind me, he's coming from the right side," Sagan added. "Mark was coming pretty fast from the back and after I just didn't have time to react, to go left, and he just came (into) me and after into the fence."
A medical team quickly ran out to treat Cavendish, jogging into the oncoming stream of riders to reach him.
When Cavendish was finally helped to his feet, his jersey was badly torn and blood was streaking down his side. Cavendish rode in with a teammate after treatment, gingerly holding his right arm close to his body, with his right hand in a bandage.
It's already been a difficult year for Cavendish, who came down with mononucleosis caused by the Epstein-Barr virus in April.
There was another crash earlier that delayed Tour leader Geraint Thomas, but the Welshman retained the yellow jersey since it happened in the neutral zone near the stage finish.
Thomas leads Sky teammate and three-time champion Chris Froome by 12 seconds, with third-place Michael Matthews of Australia also 12 seconds back.
Thomas scraped his knee but said it was OK.
"I hit the deck but I'm fine," Thomas said.
Demare clocked nearly five hours over the largely flat 207.5-kilometer (129-mile) route, which started and finished in two spa towns, Mondorf-les-Bains in Luxembourg and Vittel in France.
Demare's win ended a long wait for the home fans, with the previous French victory in a bunch sprint at the Tour being won by Jimmy Casper in Stage 1 in Strasbourg in 2006.
"We've been working with Arnaud for a long time on sprints," said Marc Madiot, manager of Demare's FDJ team. "Winning in the Tour is the best."
After Sagan's disqualification, Alexander Kristoff moved up to second place in the stage, with Andre Greipel in third.
Stage 5 on Wednesday concludes with the first serious climb of the Tour. The 160.5-kilometer (100-mile) leg begins in Vittel and winds its way to La Planche Des Belles Filles with a short but steep finishing ascent that features a leg-breaking 20-percent gradient in the final meters. All of the overall favorites should swing into action.