<a href="https://www.thenationalnews.com/tags/manchester-united/" target="_blank">Manchester United</a>'s interim manager Ralf Rangnick said the club requires an "open heart operation" if they are to turn things around at Old Trafford. United named Ajax Amsterdam coach <a href="https://www.thenationalnews.com/sport/football/2022/04/21/erik-ten-hag-confirmed-as-new-manchester-united-manager-on-three-year-deal/" target="_blank">Erik ten Hag as their new manager</a>. The 52-year-old signed a three-year deal and will succeed Rangnick at the end of this season. Ten Hag is the fifth permanent manager to be appointed by United since Alex Ferguson retired in 2013 following David Moyes, Louis van Gaal, Jose Mourinho and Ole Gunnar Solskjaer. Rangnick has been in interim charge since Solskjaer was sacked in November 2021. The Red Devils <a href="https://www.thenationalnews.com/sport/football/2022/04/19/mohamed-salah-stars-as-liverpool-crush-manchester-united/" target="_blank">were thrashed 4-0 by Liverpool</a> in midweek, a defeat which left them in sixth place in the table, 23 points behind leaders and neighbours Manchester City. They also face an uphill struggle to reach the Champions League next season, three points and a spot behind Arsenal, who have a game in hand. The teams will face each other on Saturday. "You don't even need glasses to see and analyse where the problems are," Rangnick said. "Now it's about how do we solve them? It's not enough to do some minor amendments – cosmetic things. In medicine, you would say that this is an operation of the open heart. "If this happens and everyone has realised that this has to happen and if people want to work together then it makes sense. I believe it doesn't take two or three years to change those things. This can happen within one year." However, Rangnick backed new manager Ten Hag to deliver, saying there was enough evidence to suggest the Dutchman can turn the club's fortunes around. Ten Hag was appointed by Ajax during the 2017/18 campaign and led them to the Dutch league title in 2019 and 2021, as well as the Champions League semi-finals in 2019. "We don't know each other in person but from what I've seen of him with Bayern Munich [reserve team] and Ajax now, I like his football," Rangnick said. "I'm pretty positive with a full pre-season and having the chance to build and mould his own staff with a new team, we'll see a different team and improvement on the pitch. "I knew he was a candidate and told the board from what I had seen that he would be a good choice." "The most vital part is that the club manages to get in the best possible players and we have the attitude, the energy," Rangnick added. Meanwhile, Rangnick revealed midfielder Paul Pogba, who is set to miss the remainder of the season with a calf injury, will not renew his contract with the club. "As it seems right now, he will <a href="https://www.thenationalnews.com/sport/football/2022/04/20/the-football-stars-out-of-contract-this-summer-mbappe-pogba-modric-and-more/" target="_blank">not renew his contract</a>. Maybe the club or Erik will also not want to renew the contract, I don't know, but it's most likely he won't be here anymore next season," the manager said.