Arsenal midfielder Mikel Arteta says he would be surprised if Manchester United failed to mount a Premier League title challenge this season.
Ahead of the Gunners' trip to Old Trafford, David Moyes's men sit eight points behind Arsene Wenger's side after 10 matches.
Arteta, who worked with the Scot at Everton, believes that United possess the players required to successfully defend their title this term and warns that it will be tough for Arsenal to secure three points in Sunday's clash.
"I am expecting them to be there because with the quality they have," the 31-year-old Spaniard told his club's official website.
"When you look at the squad, the players, the quality they have and experience as well. If you mixed that all together then obviously it becomes something good so I will be surprised if they're not.
"[Moyes] is a big winner and, for sure, they are looking much better now. They won a few games in a row and it will be tough to win there.
"It's another massive one and we had a few in the last few days. We will just get back and get ready physically for the next step because as you know it will be really hard against Manchester United."