The English FA are likely to investigate the incident at the end of Chelsea's FA Cup quarter-final win at Tottenham when a fan appeared to aim a punch at Frank Lampard.
The supporter ran onto the pitch after the final whistle of the replay at White Hart Lane last night following the visitors' 2-1 victory which keeps Jose Mourinho's side in the hunt for a quadruple.
Chelsea's win, courtesy of stunning goals by Andriy Shevchenko and Shaun Wright Phillips, sets up a semi-final with Blackburn but the result was overshadowed by the ugly scenes afterwards, with at least one other fan getting on the pitch.
"I saw the guy coming and wanted to keep my eye on him because if I turn my back, I thought I might get one on me," Lampard said. "I just ducked and the stewards got to him. The way he ran at me I think he'd had a few drinks.
"I don't think he should have been on the pitch in the first place, but you can understand there's a lot of emotion in a match like this."
Police confirmed that one fan had been arrested for encroaching and suspicion of assault and another had been arrested for encroaching.
Shevchenko found the top corner 10 minutes into the second half, with Wright-Phillips steering a volley home before Robbie Keane pulled one back from the penalty spot.
Chelsea boss Mourinho said: "The most important thing is how the team fought - together and well-organised. This team is committed to the reaching the final, we showed that we very much want to be there."
Spurs boss Martin Jol was left to rue his side losing a 3-1 lead at Stamford Bridge in the initial tie.
"You can't say the best team has won but it was a great goal from Shevchenko," said the Dutchman. "We've got players who can do that and they did that away from home against Chelsea."
Jol did not shake Mourinho's hand at the final whistle but saw him afterwards.
Of the incident with Lampard, Jol added: "It's not something you like to see. You don't want that, but I can feel for the frustration and it was evidence that everyone felt we could do something today."
Mourinho and Jol had good news for England boss Steve McClaren, who watched the game in the stands, by reporting no fresh injury worries among the England players in both squads.
