London - Wigan announced a full investigation on Tuesday into crowd disturbances that marred the club's dramatic FA Cup victory over Premier League leaders Manchester City.
City striker Sergio Aguero became involved in a physical exchange with a Wigan supporter as thousands of fans spilled onto the pitch following the League One side's 1-0 victory in the fifth-round tie on Monday.
TV footage of the chaos at the DW Stadium appeared to show Aguero raising his arm to push away the fan and later having to be restrained. It is understood Aguero claims he was spat at.
A number of fans also headed towards the end where City supporters were sitting to continue celebrations, sparking further disturbances..
Advertising hoardings were ripped out and thrown onto the pitch along with other objects, while missiles were also thrown from the pitch into the stand. There were also clashes between fans and police and stewards.
Police made two arrests on suspicion of affray following an incident outside the ground.
"While we appreciate that the vast majority of supporters who ran on to the pitch did so spontaneously to celebrate a famous victory, we were disappointed with the action of a minority of supporters who acted in an inappropriate manner," said Wigan chief executive Jonathan Jackson.
"Player and staff safety is of paramount importance and we will conduct a full investigation."
Chief Superintendent Stuart Ellison of Greater Manchester Police said such behaviour would not be tolerated.
"As soon as people were on the pitch, we immediately deployed our resources to the front of the stands, where they were able to keep the two groups of supporters apart and prevent any further disruption," he said.
Police added in a statement that no injuries had been reported.
The Football Association is assessing the situation but is yet to say whether either club will be investigated. The report of referee Anthony Taylor and video footage will be taken into account.
The governing body could also look into a confrontation between City manager Pep Guardiola and his Wigan counterpart Paul Cook. The pair exchanged heated words after City's Fabian Delph was sent off late in the first half.
Their argument continued in the tunnel after the sides left the field at half-time and television pictures showed Guardiola having to be held back by colleagues.
Guardiola later played down that incident, suggesting he had been annoyed that Cook had left his technical area.
"Nothing happened in the tunnel, nothing happened with my colleague," the Spaniard said. "It was just 'please stay in your position', that's all, and then finished."
Wigan's victory, courtesy of a 79th-minute strike from Will Grigg, ended City's historic quest for a quadruple.