Sir Alex Ferguson's side edged to victory in a 4-3 thriller against Reading on Saturday but the midfielder was disappointed with his side's defensive display.

Carrick told the Manchester Evening News: "That's the standards we set. We're not happy until we know we're playing to our potential. The pleasing thing is there's a lot more to come from us.

"There's a lot more room for improvement in certain aspects of our play but at the same time we're sitting on top of the league and we've won again.

"We can't get too down about things, there are a lot of positives."

United fell behind early at the Madejski Stadium but came back twice before netting what turned out to be the winner in the 34th minute of a frantic first half with Robin van Persie's 10th league goal of the campaign.

Although United showcased defensive frailties, the England international said he always had faith in their ability to come back.

"Even if we do go a goal down we always feel we've got the firepower from different people," Carrick said.

"That's the strength in depth of the attacking options and that's what keeps driving us on and we never give up.

"Personally I always felt confident, even when we were going goals behind, that we could still get back in the game and win the game, and that obviously proved the case."