Ireland's Sam Bennett was demoted for shoving another rider on stage nine of the Vuelta a Espana.
The Deceuninck-Quick-Step sprinter, who won the green jersey at the Tour de France, muscled his way across the line first on the stage into Aguilar de Campoo, near Bilbao.
But he was demoted after race commissaires said he shoulder-charged Emils Liepins of Trek-Segafredo.
Germany's Pascal Ackermann of Bora-Hansgrohe inherited victory.
Ineos Grenadiers' Richard Carapaz remains in the overall lead, with Britain's Hugh Carthy fourth.
The 157.7km stage from Castrillo del Val near Burgos was a largely soporific race on wide, pan-flat roads.
But Bennett showed the strength and efficiency which saw him win on the Champs-Elysees in Paris in September to finish a bike wheel ahead of Ackermann of Bora-Hansgrohe and Belgian Gerben Thijssen of Lotto-Soudal.
But Bennett, who thought he had secured his 50th career win, said before his demotion he had been involved in a tussle with other riders before the final sprint.
"It was slightly uphill and a headwind," said Bennett. "But we had to come from behind at speed.
"There was a big fight with some guys who nearly put us in the barriers trying to take the wheel, so it was a bit sketchy trying to stay upright."
In another incident during Thursday's stage Caja Rural's Hector Saez suffered a nasty fall in which his head struck the ground, shattering his helmet.
He was checked over by officials and allowed to rejoin the race.
The incident fuels questions about how the sport deals with head injuries and potential concussions, following Romain Bardet being allowed to finish stage 13 of the Tour de France despite suffering a bleed on the brain after a crash - as well as several other recent examples during this season's Grand Tours.
In the overall standings Ineos' Carapaz maintained his 13-second lead over Primoz Roglic of Jumbo-Visma, with Dan Martin of Israel Start Up Nation 28 seconds down and Carthy of EF Pro Cycling 44 seconds behind the wearer of the red jersey.
How has Froome been getting on?
Ineos' Chris Froome has been showing signs of steady improvement after losing time at the start of the race a week ago.
The four-time Tour de France winner, 35, spent much of Thursday near the front of the peloton expending energy for his team in protection of leader Carapaz.
Froome's improvement will be welcome for Ineos and his new team Israel Start Up Nation, with whom he will ride for from 2021 after Ineos decided not to renew the Briton's contract.
Froome had struggled to keep pace during races in the lead up to the Tour de France in late August, leading to Ineos deciding not to select him to take part in the cycling's biggest race, as he recovered from a horrific crash in 2019.
Ineos said Froome is enjoying his role in the team as he reacclimatises himself with racing conditions in Spain.
Friday's stage is another flat sprinter's race from Castro Urdiales to Suances.
Stage nine result
1. Pascal Ackermann (Ger/Bora-Hansgrohe) 3hrs 39mins 55secs
2. Gerben Thijssen (Bel/Lotto-Soudal) same time
3. Max Kanter (Ger/Sunweb)
4. Jasper Philipsen (Bel/UAE-Team Emirates)
5. Jakub Mareczko (Ita/CCC)
6. Alexis Renard (Fra/Israel Start Up Nation)
7. Jon Aberasturi (Spa/Caja Rural)
8. Lorrenzo Manzin (Fra/Total-Direct Energie)
9. Robert Stannard (Aus/Mitchelton Scott)
10. Janse van Rensburg (Rsa/NTT)
1. Richard Carapaz (Ecu/Ineos Grenadiers) 32hrs 31mins 6secs
2. Primoz Roglic (Slo/Jumbo-Visma) +13secs
3. Dan Martin (Ire/Israel Start Up Nation) +28secs
4. Hugh Carthy (GB/EF Pro Cycling) +44secs
5. Enric Mas (Spa/Movistar) +1min 54secs
6. Felix Grossschartner (Aut/Bora- Hansgrohe) +3mins 28secs
7. Esteban Chaves (Col/Mitchelton Scott) same time
8. Alejandro Valverde (Spa/Movistar) +3min 35secs
9. Marc Soler (Spa/Movistar) +3min 40secs
10. Wout Poels (Ned/Bahrain-McLaren) +3min 47secs
111. Chris Froome (GB/Ineos Grenadiers) +1hr 40mins 44secs