Cesc Fabregas has denied allegations that he spat at Hull City's assistant boss, Brian Horton, following Arsenal's FA Cup victory over the Tigers.
City boss Phil Brown claimed that Fabregas, who was injured and not playing, had spat at Horton in the Emirates Stadium tunnel moments after the final whistle.
"That's their club captain," said Brown. "I hope he feels proud of himself."
Arsene Wenger later said that he knew nothing about the incident and Fabregas has now pleaded his innocence.
"I categorically deny that I spat at anybody after the match," he said in a statement on the club's official website.
"I have never done this in my whole career on the pitch, so why would I do it when I am not even playing? I can understand the frustration of losing a game to a dubious goal, that has happened to me many times in my career as well. But this is not the fault of me or any of the Arsenal players."
Brown later insisted Horton will receive the club's 100 per cent backing if he decides to take the complaint further.
"Brian will receive the full support of the people of Hull, that includes my chairman, who we had a long conversation with this morning," he said.
"We'll go down the right channels and support Brian Horton."
Speaking about his frosty relationship with Wenger, Brown added: "It just shows how we've got up the noses of the Arsenal hierarchy. He wouldn't shake my hand when we beat them fairly 2-1 at the Emirates, he wouldn't shake my hand when they beat us, fairly, 3-1 at the KC Stadium."
The Football Association is aware of the allegations but will await referee Mike Riley's report and any possible formal complaint from the Tigers' coaching staff.