Arsenal defender Per Mertesacker has admitted that losing to Liverpool on Saturday is one of the "worst setbacks" that the Gunners have faced so far this season.

The North London outfit were thrashed 5-1 by Liverpool at Anfield and have since lost their place at the top of the Premier League table.

"To be honest, it's one of the worst setbacks of this season," Mertesacker told the club's official website.

""We feel very bad at the moment, disappointed with our performance right from the start. It was just not good enough to compete at that level. Liverpool seemed full of confidence.

"At the start we were eight points clear of Liverpool so we should have been more confident and more aware of the situation but that wasn't the case."

The Gunners will have the chance to respond when they take on Manchester United at the Emirates Stadium on Wednesday.