Arsenal will need to be at their best even if Manchester United field a weakened team on their Premier League visit on Sunday, manager Arsene Wenger has said.
Both sides need a win to stay in the hunt for Champions League qualification, with Arsenal at risk of missing the top-four for the first time in two decades.
United manager Jose Mourinho has hinted he will prioritise the Europa League as he seeks a Champions League berth by winning Europe's second-tier competition, but Wenger does not believe that will give Arsenal the upper hand on Sunday.
"The only advantage we can give is to focus on ourselves, not a weaker Manchester United," the Wenger told a news conference on Thursday.
"We know anyway they have a massive squad with quality players and only a top performance will get us the win we want.
"Now even winning our games does not guarantee us to be in the Champions League, that is what we have to achieve."
With seven victories in last 16 games in all competitions, Arsenal's campaign has lost its momentum. Pressure is mounting on the club to replace Wenger, whose current deal expires at the end of the campaign.
On being reminded that he was scheduled to make an announcement on his future at the club in March or April, Wenger said, "We are in May, that means I was wrong."
The Arsenal boss admitted his relationship with former United manager Alex Ferguson "mellowed" over time and he is open to similar progression with Mourinho, despite a decade-long history of rivalry between the two managers that at times has descended into pettiness and acrimony.
"I'm open always in life for everything, for peace, but what is important when you are a competitor is that you give everything to win the next game," the 67-year-old Frenchman added.