A English fan was stabbed to death in Lisbon early today when a pickpocket targeted fans celebrating England's victory over Croatia in the Euro 2004 tournament.
Witnesses said the killer struck at around 4am as hundreds of fans were toasting England's triumph.
The victim was named by sources in Portugal as Stephen Smith, 28, from Wolverhampton, West Midlands.
Sources said Ukrainian pickpocket Vadym Abramov, 31, was arrested in connection with the killing and was appearing in court today.
Haskell Noah, 35, a delivery driver from Golders Green, north west London, said: "It was about four in the morning and there were about 200 England fans sitting around at tables having a drink and a laugh.
"This guy had been coming up and down for hours trying to take people's wallets and everyone was fed up with him.
"We'd been telling the police about him but they didn't do anything.
"An England guy pushed him away, he went away and came back about two minutes later and went straight over to a different guy just sitting at a table and stabbed him."
Mr Noah said there was an immediate commotion and the stabbed fan fell to the ground.
"A girl was screaming and police came running across to arrest the attacker as he ran away.
"They got him on the ground and got the handcuffs on him."
The stabbing happened at around 4am off Rossio Square in the Portuguese capital, police spokeswoman Isabel Canelas said.
She said the suspect was likely to appear in court later today charged with causing death by stabbing.
The injured fan was taken to Lisbon's Sao Joseph Hospital after the stabbing but died from his injuries.
Earlier reports suggested a Croatian man had been arrested over the attack.
But police sources later confirmed that the man was from the Ukraine, which has not got a team in the tournament.
Thousands of England fans poured into the square after David Beckham's men booked themselves a place in the quarter-finals of Euro 2004 with a 4-2 victory.
There had been fears that a hard-core of Croatian fans were looking for trouble, but the post-match celebrations in the city were largely peaceful.
England fans dominated the 65,000 capacity Estadio da Luz last night, with an estimated 40,000 supporters making the trip to Lisbon.
The stabbing happened in the Rua Augusta where many England fans were celebrating outside bars just off the Rossio Square.
Police said the Ukrainian suspect was a well-known pickpocket who earns his living from stealing the wallets of tourists.
It is believed he tried to steal the wallet of an English fan but was spotted and confronted.
He is then alleged to have pulled out a knife and stabbed one of the supporters before running away.
Undercover and uniformed Portuguese police were close by and chased the Ukrainian and arrested him immediately.
Ms Canelas said: "It came out of the blue, he just pulled the knife out and did this."