Keane, who was suspended on Saturday, looks certain to return for the visit of the European Cup holders. Karel Poborsky is likely to make way for Keane as United aim for the victory which could be enough to earn qualification for the quarter-finals.
Juventus have already qualified, but the other place is still open. In theory any of the three other teams in the group - United, Fenerbahce and Rapid Vienna - could go through. However, a United victory on Wednesday, combined with a draw between Rapid Vienna and Fenerbahce in the night's other Group C tie, would put Alex Ferguson's team into the last eight.
United's last game in the group, on 4 December, is away to Rapid Vienna (Fenerbahce are away to Juventus on the same night) and United would dearly like to have qualified before then.
"We have got to win the game on Wednesday," Giggs said. "Losing to Arsenal would not have been the end of the world, but with Juventus we just have to get a result."
United will allow supporters to bring flags and banners into Old Trafford on Wednesday in an attempt to create a rousing atmosphere in the ground.
Ferguson said the crowd's support on Saturday had been a telling factor against Arsenal. "Sometimes you forget how young this side is - they would rather have encouragement than criticism and that was shown today," he said.
"The problem is we have a lot of people come here as visitors, who sit and admire, and enjoy the day out. It is a bit of weekend holiday for them. That's all very well, but it's no use to me or the players. When you have support like you had today, with 55,000 here cheering you on, it makes all the difference, no doubt about that."