Mark Cavendish had urine thrown at him by a spectator during Wednesday's stage 11 time trial in the Tour de France.
Although the Manxman declined to answer questions after completing the 33km stage from Avranches to Mont-Saint-Michel, his Omega Pharma-Quick Step team confirmed what had happened out on a course packed with fans.
Team manager Patrick Lefevere said: "I regret this. I always felt that cycling fans were gentlemen, enthusiastic people.
"Mark is sad. He is not upset - just sad. I cannot blame anyone. There are 100,000 or 200,000 people on the road, and one person decided to do this."
The incident came after the British national champion was embroiled in controversy on Tuesday, when a crash late on stage 10 sent Tom Veelers to the floor and ended Cavendish's hopes of a stage win.
Although the Briton was cleared of any blame by the race organisers, many fans condemned his actions on social media.
Cavendish's French team-mate Jerome Pineau was the first to confirm that the reaction had escalated out on the course this morning.
"Yesterday I was so proud to see the support at the race but today I am ashamed," he wrote on Twitter.
"Ashamed when my friend @MarkCavendish tells me he has been whistled and even sprayed with urine on the course. It is scandalous."
Cavendish remained on the team bus after the stage and offered only a shake of the head when asked to comment on the incident, but another member of staff said with a grin that there had "been a smell" when the Manxman returned to their bus.
Cavendish was among the early runners in today's time trial due to his lowly position in the general classification, and set a time of exactly 42 minutes.