Wes Brown expects Arsenal to show their mettle tomorrow at Old Trafford after they were knocked out of the Champions League by Liverpool.
It could be bleak week for the Gunners as defeat at the hands of Manchester United would all but end their title challenge.
They are currently six points adrift of Sir Alex Ferguson's side and three behind Chelsea.
Brown, however, knows Arsenal are traditionally tough opponents.
He said: 'They will be disappointed at what happened against Liverpool.
'But I think, if anything, they will try and prove to everyone in the game they are still in the title race.
'We have to be prepared for that - and I am sure we will be.
'We've got a lot to play for. If we can beat Arsenal we'll be in a great position with four games to go.'
Cristiano Ronaldo is almost certain to be restored to the United team after being rested in midweek when they reached the semi-finals of the Champions League with a 1-0 win over Roma.
The Portugal winger has been named Barclays Player of the Month for March while Ferguson receives the Manager of the Month award.
Ronaldo scored four times in that period while United won every league game without conceding a goal.
With 37 goals for his club to his credit this season, the 23-year-old is closing in on Denis Law's Old Trafford record of 46.
And Ferguson sees similarities in the players that span the generations.
He said: 'Denis had an incredible spring, which Ronaldo can relate to.
'Considering he was about 5ft 9ins, Denis was good in the air when you take into his account his height.
'He was lightning quick in the box as well. If anyone made a mistake, the ball was in the net.
'Denis and Ronaldo are great players. It is always hard to score a goal, I can assure you of that.'
Meanwhile, Ferguson admits he is disappointed with the kick-off time for the potential title decider against Chelsea at Stamford Bridge.
The Barclays Premier League match on April 26 is scheduled for a 12.45pm start and will be live on Sky Sports.
Ferguson is concerned about his players' recovery time as United face Barcelona at the Nou Camp in the Champions League semi-final first leg the previous Wednesday.
However, he has no plans to appeal to the Premier League.
'We would prefer a better kick-off time against Chelsea,' he said. 'But we have to accept it as TV are the dominant force.'