Ralf Rangnick has told his Manchester United players to prove they care and are not reverting to their bad old ways.

The interim manager demanded "passion, emotion and intensity" ahead of Monday's FA Cup third-round home clash with Aston Villa, and admitted there are players who are unhappy within the Red Devils' ranks.

A dismal Premier League home defeat to Wolves halted early progress during Rangnick's reign, and the German boss said on Friday said it was "a step back... maybe a relapse".

Rangnick inherited the job from Ole Gunnar Solskjaer, the club legend who was sacked once it became clear he could not get the best from United's talented and costly set of players.

Now that is the challenge for the experienced former RB Leipzig boss, and he has demanded the co-operation of the squad as a whole.

"We have made some progress, but obviously the game against Wolves was a step back, maybe even a relapse to habits the team has shown in the past," Rangnick said in a news conference.

"We need to insist and emphasise every time that we have to work together."

He repeatedly pointed to finding a balance between defence and attack, and called for a collective, fiery effort.

"We need to do it with passion, with emotion, with intensity," Rangnick said.

"This was the problem against Wolves, especially in the first half where we were only escorting them. It was only David de Gea who objected to them going easily to our goal."

Wolves had 15 shots before half-time in Monday's Premier League game, the most attempts any visiting team has had at Old Trafford in the opening 45 minutes of a Premier League game since at least 2003-04, Opta said.

Rangnick said a "different performance" was imperative for the Villa game, and said he was confident his players were making an effort to buy into his methods.

"They're at least trying, I'm sure that they are listening," he said. "We need to and want to work with the players we have.

"We've showed we can keep clean sheets, but it's also about what we are doing with the ball and without the ball. Once we have the ball it's about responsible decision-making, making the right decision at the right moment."

Villa have lost their last six FA Cup matches, their longest ever losing run in the competition, while United have won their last nine home games in the tournament by an aggregate score of 20-2.

They are unbeaten in their last 11 at Old Trafford in the FA Cup since a 2-1 quarter-final defeat to Arsenal in 2014-15.

Yet Villa have won in the league at United's home this season, so Rangnick is on guard.

History tells us there have been only three occasions of a team winning twice away at United in the same season – Chelsea in 2004-05, Tottenham in 1989-90 and Villa themselves in 1919-20. Villa, now bossed by former Liverpool skipper Steven Gerrard, would love to repeat the feat.

There have been rumours of discontent in the United dressing room, often centring around Cristiano Ronaldo, with speculation he might be unhappy or that others are disenchanted with his status.

How true any of that might be is unclear, and Rangnick says there are always bound to be players who become fed up.

"This is not only an issue with a club like Manchester United. If you have that many players and only 10 outfield players can play and three be substituted [onto the pitch], you have quite a number of players, in our case, 12, 13, 14 players who don't even play or don't even get in the squad," he said.

"Those players are not happy about that situation, it's obvious and it is clear. I tend to explain to players every two or three weeks why they are not playing, but obviously I can't do that in every game."

Some may move on during this transfer window or at the season's end.

"We have players with contracts expiring in the summer, maybe also one or two others who still want to leave, although they're on contract," Rangnick said.

"It's about the players to deal with that situation in a professional way. If I realise that is not the case I will address that to the players directly.

"Everybody has the chance and option in training to show up and get the chance to play. If this is not the case, the players together with the club and agents need to discuss the situation."