David Moyes has said there is no doubt he will repair Manchester United's faltering start to the season as he omitted Rio Ferdinand from the Champions League test against Shakhtar Donetsk.

The United manager is under early scrutiny at Old Trafford after West Bromwich Albion inflicted a third defeat in four Premier League games on the champions on Saturday. The Albion reverse included another poor display from Ferdinand, who, at 34, has started seven of United's eight matches this season but will not feature against the champions of Ukraine.

Moyes revealed the defender has a minor groin injury but would not have featured in the Donbass Arena if fit, an indication of Ferdinand's need for a rest but potentially also of the manager's decision to deploy Phil Jones as a regular centre-half. "Rio, Anderson, Fábio [da Silva] and Wilf Zaha aren't with us," Moyes said. "I was never bringing Rio anyway but he's got a slight groin problem. It's nothing serious."

For Moyes there is no escape from the scrutiny accompanying United's worst start to a season in 24 years. But, in a brief press conference appearance in Ukraine, he reiterated a belief that he will restore United's fortunes as he learns more about the squad he inherited from Sir Alex Ferguson.

"I've been in situations similar to this at Everton and Preston North End," he said. "You get on with it, you do the right things and you carry on. I haven't changed. The results will come, there's no doubt about that. We're getting to know the players and understanding them much more. I'm getting more of a feel for them and I know for one thing they are top players and that will never change."

Moyes suggested at the weekend that United were not equipped to win the Champions League because of a lack of world-class players but he insisted the Premier League champions would be giving their all to triumph in Lisbon next May. "I said that to win the Champions League you need a certain amount of world-class players. That's something we'll try to do," he said. "Of course we'll try to win the Champions League, that's part of the job at Manchester United."

Robin van Persie is fit to start for the first time in four matches, having recovered from a thigh injury. On Tuesday night Moyes added: "He's fit. We'll make a decision tomorrow whether we start him or not."