Less than four months later, and despite Vieira's summer move to Juventus, the two men who epitomised the rivalry between English football's most successful clubs of the Premiership era will meet again. Keane's Republic of Ireland and Vieira's France are locked together at the top of their World Cup qualifying group, with only the winners guaranteed a place at next year's finals. Each have three matches left and neither can afford to lose when they meet in Dublin tomorrow.
It would be the perfect setting for the two men to reignite the last of their many conflagrations. Keane remarked sneeringly that Vieira's charity work for Senegal, the land of his birth, was in contrast to his decision to play football for France instead; Vieira noted that the comments came from a man who had walked out on his country just before the start of the last World Cup.
Vieira, however, has been pouring water on the flames. "The English media make a lot out of our rivalry," he said at the French training camp in Lens. "But what's important is that we have respect for each other. It's all part of the game. We've had our moments, but they've been within the laws of the game and in the context of the respect we have for each other.
"There are other players to worry about, like Robbie Keane and Damien Duff. They can make a difference, though there's no doubt that Roy Keane is their most important player. He's their leader. He drives them forward. He can dictate the rhythm of the match."
The French are expecting a highly physical game, but Thierry Henry pointed out that many of the players from both sides meet each other regularly at club level. "It's like that every weekend in England," he said. "It will be a physical battle. People want to set it up as a Roy Keane-Patrick Vieira confrontation, but more than that this is a game between France and Ireland."
Vieira added: "They will try to intimidate us and the more one-on-one physical duels that we can win the better it will be for us."
The return from international retirement of Zinedine Zidane has seen Vieira lose the captaincy and switched, against the Faroe Islands last Saturday, to an unfamiliar position on the right of a midfield three, behind Zidane and two strikers. "I prefer playing in the centre," he admitted. "I had trouble getting my bearings against the Faroes. It was fine from a defensive point of view, but I struggled a bit when we were going forward and I was trying to support 'Zizou' and the strikers. But from the team's point of view it's important that Zizou, Claude Makelele and Lilian Thuram have come back."
Nor was Vieira complaining about losing the captaincy. "I was very proud and happy to be captain," he said. "Now Zizou's the captain, but it's not as though he's stolen it from me. He was captain before he retired so it's logical that he should be captain now. We talked about it with the coach. I've known Zizou for a long time."
Vieira's manager at Arsenal, Arsène Wenger, who watched the 3-0 victory over the Faroes, says the Ireland game will be a major test for a team which has been reinvigorated by the return of Zidane, Thuram and Makelele. "What they've brought back is a feeling of comfort when France have the ball," he said. "There's more serenity in the team. They keep the ball longer. They give you more time. And the overall technical level of the team has suddenly gone much higher. Zidane's comeback has transformed the team. He's raised the whole country's hopes. When he came off against the Faroes, France were immediately not the same team.
"One of the characteristics of the really big players is that they make everybody around them better. He's at the age where he can make that happen. He still has the individual skill, but with his maturity he's developed that generous attitude to make everyone around him better. That's what happens with the great players."
As for Vieira, does Wenger expect his former captain to renew acquaintance with Keane in traditional style? "I think they're used to each other," he said. "There's a mutual respect. I don't think their meeting will be special."
l Jackie McNamara, one of only two members of the present Scotland squad to have played in the World Cup finals, announced yesterday that he will retire from international football unless the current qualifying campaign leads them to Germany next summer. The 31-year-old Wolves defender is poised to win his 33rd cap tomorrow as the Scots travel to Oslo to face Norway.