Manchester United manager Louis van Gaal has described Arsenal as the best "technical and tactical" team in the Premier League ahead of their meeting on Sunday.
The league leaders travel to the Emirates Stadium for a crucial clash and the Dutchman acknowledged the quality of his side's opponents.
However, he did say Arsenal needed to improve as they should have won more in recent years given the quality Gunners manager Arsene Wenger has at his disposal.
"Arsenal are technically and tactically the best team in the league," said the 64-year-old.
"Nevertheless, they haven't won so much, so you have to look for that improvement with that team.
"We are happy but I think Arsenal can come back from a defeat. They have shown that a lot of times."
Van Gaal claimed his players were already starting to look tired following a busy run of fixtures having battled to a 2-1 Champions League win over Wolfsburg on Wednesday.
"The solution is recovery, recovery, recovery," he continued. "That is why it is so difficult to prepare for the match against Arsenal.
"We have to see how the evaluation is from my fatigue specialist."
Van Gaal also revealed key midfielder Michael Carrick has been passed fit to play in the game.
He added: "Carrick can play so I have a choice. I am happy to say that there are no injuries from Wednesday night."
