Manchester United cannot keep changing their manager and Ole Gunnar Solskjaer should be given time to prove his worth, according to Robin van Persie.

Van Persie and Solskjaer had a public feud last month when the Dutchman urged the United boss to show more anger after a defeat to Arsenal.

Solskjaer did not take kindly to the suggestion, saying while Van Persie took his famous number 20 shirt at Old Trafford, he had no right to criticise his managerial style, vowing not to change.

But despite that spat and the club sitting seventh in the Premier League, the ex-United forward feels constant managerial changes are not beneficial.

If Solskjaer is United's man, Van Persie says they simply have to give him time.

"Especially after Alex Ferguson left, everyone realised that it would be tough to stick to that level that Ferguson achieved for all of those years," Van Persie, speaking courtesy of Enterprise rent-a-car, told Omnisport.

"I think everyone could see that. Now [David] Moyes has been there, [Louis] van Gaal, [Jose] Mourinho and Solskjaer. 

"Ferguson took time to adjust and get to a certain level. I don't think that it's ideal for the club to keep changing the manager every one or two years. 

"If you go for Solskjaer, go for him and give him time, that is what I think because the club needs to find some stability."

United had an encouraging 2-0 win at Chelsea on Monday, putting them within three points of the top four in the Premier League.

Van Persie was impressed by the display but feels a lack of consistency is holding United back against elite competition in the form of Liverpool and Manchester City.

"Now they win against Chelsea and to be fair they had a good game," added Van Persie.

"But you never know what's going to happen in the next few games. It's not consistent enough to be able to really play for the trophies. 

"It is difficult because you have to compete against Liverpool, who are unbelievable and Manchester City, who are brilliant. 

"Manchester City are not on the same level this year, but based on the last couple of years, they and Liverpool have been unbelievable. 

"That is the level United have to go to, that is consistency, and that is the hardest thing in football because the league is tough. 

"Even if you play against teams like Burnley away, teams like that are really difficult to get points against. You have to get everything right and that is a big challenge to get that consistency."

With United bidding to get back into the Champions League through a top-four finish, the Europa League gives them another avenue to the continent's elite club competition.

Solskjaer's men play Club Brugge in Belgium on Thursday in the first leg of their last-32 tie, with Van Persie seeing Ajax as the biggest rivals to United and Arsenal, another of his former teams.

"Arsenal and Manchester surely are the favourites to win," he said. 

"Ajax were knocked out of the Champions League in a harsh manner. That is also part of the game, unfortunately. They also have a chance at winning the Europa League and have a very good squad too.

"In the Europa League, Premier League clubs tend to field a mix of players up until the knockout phase. From this point on, they tend to use their best 11. Up until now it's been a mix between first-team players and substitutes. 

"I think they are in it to win it. That is the way they should prepare because it is a great title that is up for grabs."