United went on to claim a famous 4-2 victory and move into second place behind runaway leaders Chelsea, but the action began even before the first whistle had sounded.
Television cameras caught Keane furiously shouting and pointing at Vieira in the tunnel as the players walked out for the start with referee Graham Poll forced to intervene.
United manager Alex Ferguson told Sky Sports that Vieira had started the latest bout of trouble between the two clubs.
"I've heard different stories. Patrick Vieira has apparently threatened some of our players and things like that," he said.
"So he was well wound up for it," the Scot added with a laugh.
Keane said: "If people want to intimidate some of our team mates, let's have a go at some of the other players. They think Gary Neville is an easy target, but I'm not having it."
France international Vieira, who gave Arsenal the lead after eight minutes, would not be drawn on the spat with Keane.
"I think Gary Neville is a big boy and he can handle everything by himself. I didn't try to threaten anybody else. I don't want to talk about it."
The heated exchange followed weeks of hype over the fixture after the infamous pizza-throwing melee at Old Trafford following United's controversial 2-0 victory in October that ended Arsenal's 49-match unbeaten league run.
Since that clash Ferguson and Arsenal manager Arsene Wenger have traded regular insults in the media, with their prickly relationship reaching an all-time low in recent weeks with both summoned to a meeting with the Football Association.
