Michael Carrick believes Manchester United are capable of returning to the heights they reached under Alex Ferguson, although he warned that the process will require patience.

According to Free Malaysia Today, the United manager made the remarks at a press conference on Friday ahead of Sunday's Premier League fixture against Aston Villa, a game that could turn out to be his last at the helm.

Carrick's side ended a nine-match run without a win on Tuesday, recovering from two goals behind to defeat Roma 3-2 in the Champions League. Their league form remains a serious concern, however. United have not won a Premier League match since August and are only above the relegation places on goal difference.

The club's board has given Carrick more time, but the report notes that the two-week international break after the Villa game offers a window to replace him unless he can demonstrate that the team is heading in the right direction.

Carrick was a player during United's most successful era under Ferguson, when the club collected several major honours. Results have dropped considerably since the Scot retired following the 2013 season, which delivered United's most recent Premier League title.

Asked whether matching that success was beyond reach, Carrick rejected the idea. "It's not impossible. Anything is possible," he said.

He added that progress would not come quickly, stressing that consistency was essential and that there were no shortcuts. Carrick pointed to the improvement the team made last season as evidence of what could be achieved, but said maintaining it was the real challenge.

The win over Roma came at a cost, with Carlos Baleba, signed for £70 million (US$93 million), ruled out for the foreseeable future with a hamstring injury.