The Dutchman returns to the Emirates having left to join United in the summer in a £24m deal, with some Gunners fans still angry at his departure.
Van Persie has been a huge success at Old Trafford, scoring 28 goals to help Sir Alex Ferguson's side reclaim the title from rivals Manchester City, with Monday night's 3-0 win over Aston Villa securing the crown.
But with Arsenal still chasing points to secure their place in the Champions League for the 16th season in a row, Spain left-back Monreal is keen for his side to steal the limelight from Van Persie.
"Teams like Manchester United don't just have gifted wingers, they have a squad with a lot of depth," said Monreal.
"Their players are of the highest level, you can't just focus on one player because their team is full of players who can create and score.
"We must be on our guard and be aware of certain key players, like Robin, who has scored a sack of goals this year and is playing well. He is one of their main threats.
"They are one of the biggest teams in England and they are having an exceptional season.
"It is one of those games every player wants to be involved in, but there are three points at stake and that is what we are aiming for.
"They may be a very strong opponent, but we are also a very good team and can win the match."
Arsenal striker Olivier Giroud misses the game as he begins a three-match suspension after being sent off in their 1-0 win over Fulham.
The Gunners decided to appeal the red card for the Frenchman's challenge on defender Stanislav Manolev but it was rejected by the FA on Tuesday and manager Arsene Wenger admits he was unhappy with the decision.
"It is a blow that we cannot have him available. We will have to do without him and we will do it," said Wenger.
"It is a harsh decision. After the game, I was a little bit less convinced that he didn't deserve the red card, but having seen it again, I feel it is completely accidental and a very minor incident.
"That is why I decided to appeal. I am sad that it didn't work, but we have to cope with it."