(CNN) -- British police are investigating an allegation of common assault against Inter Milan manager Jose Mourinho following his club's 2-0 defeat against Manchester United in the Champions League.
Jose Mourinho applauds supporters at Old Trafford following his team's defeat against Manchester Utd.
It has been alleged Mourinho punched a supporter close to the Inter team bus as he left the stadium on Wednesday evening following the match in Manchester, northern England, The British Press Association said Thursday.
A statement on the Greater Manchester Police Web site confirmed that "at 11:55 p.m. a man reported he had been punched in the face on Sir Matt Busby Way, outside Old Trafford Football Stadium."
The police have also contacted the club to request CCTV footage of the area, PA said.
Inter Milan have denied Mourinho was involved in any incident and issued a statement on Thursday to back up their claim.
"At the end of the game, the Portuguese tactician gave interviews to the European media, signed autographs, watched the penalties of the Roma v Arsenal game before saluting (Sir Alex) Ferguson in his office," it read.
"After giving the last interview to Inter Channel, he entered the team bus that was parked outside the dressing rooms and hence it was a very calm post-game experience."
The supporter who made the allegation is understood to be from East Anglia, in eastern England, and claimed he was hit because he was singing a football song Mourinho didn't like, The Manchester Evening News added.
According to the same newspaper, Mourinho has not yet been contacted about the allegation as he was on board the flight back to Milan as the complaint was being made. It is understood the fan made the complaint at Stretford Police station, close to the stadium, at 12.20 a.m.
A spokesman for Manchester United confirmed they are aware of the allegation but made no further comment.
The clash between the two clubs was given added impetus by the fact Jose Mourinho, who refers to himself as "the special one," was facing up to his old rival in the English Premier League, Alex Ferguson.
The super confident former Chelsea boss had only lost once to Ferguson in 12 previous clashes and famously his then Porto side knocked United out of the Champions League at the semifinal stage in 2004.
However, Mourinho's bravado -- and occasionally abrasive style -- has won him few admirers in his first season in Italy, despite the fact his team enjoy a healthy lead at the top of the Serie A.
Earlier this month, he was charged by the Italian football authorities with making "harmful remarks to the reputation of referees," after he alleged rivals Juventus had benefited from mistakes by match officials.