Despite a run of two defeats in 16 Barclays Premier League matches, Manchester United’s place in the top four does not look as solid as it did at the turn of the year. Although Southampton have dropped to fifth they remain just one point behind United while Liverpool’s upturn in form has pushed them to within two points of their rivals. Liverpool’s exit from the Europa League should aid their pursuit of a top-four finish and the same applies for Tottenham, who are just three points shy of Van Gaal’s side. Van Gaal believes all four teams and third-place Arsenal are involved in an almighty scrap for the final two Champions League places and that is why he thinks victory over Sunderland on Saturday is vital. ”It is because of the rat race between five clubs that we have to win, we have to be there,” the United manager said. ”You have to win your matches because the other clubs are winning their matches.” The bad news for Van Gaal is that he looks likely to be without Robin van Persie for at least two weeks because of an ankle injury he suffered in the 2-1 defeat at Swansea last weekend. Van Persie left the Liberty Stadium on crutches and scans have shown he is likely to be unavailable for some time. ”He has an ankle problem,” Van Gaal said. “But I don’t think it’s very heavy but an ankle problem takes a long time. It’s not one week or two weeks but we have to wait and see.” Press Association Louis van Gaal cannot bear to think about failing to escape from the frantic “rat race” he is currently involved in. It is hard to imagine Van Persie will be fit to face his old club Arsenal a week on Monday in the FA Cup and even the fixture against Tottenham six days later could be a problem for the Dutchman. Although he has scored only 10 goals this year, Van Persie’s experience is vital to the team’s success. The Dutchman, who reached the Champions League final with Arsenal in 2006, no doubt watched with envy this week as his former club and Manchester City took on Monaco and Barcelona respectively in the competition. Van Gaal admits it would be a huge let down if United did not make the top four – and took issue with the media for even contemplating the possibility of his team failing to qualify for the biggest cup competition in club football. ”[It would be a] big disappointment [not to qualify],” said Van Gaal, who won the Champions League with Ajax 20 years ago. ”When you start the season with the objective of finishing in the first four of the league it is your objective and you are occupied with doing that. ”But we are still there, I don’t know why are we talking about it when it is not like that, because we are still there. What is the problem?” Van Persie’s absence increases the chances of Radamel Falcao being brought back into the starting XI. Elsewhere, Michael Carrick is back in training after a five-week calf injury lay-off but the midfielder is unlikely to be risked on Saturday. Sunderland boss Gus Poyet is determined to give his star men the freedom to fashion another famous victory over United at Old Trafford. Poyet limps into the game on the back of a dismal goalless draw with West Brom last week and an FA Cup defeat at Bradford which raised some speculation over his future at the Stadium of Light. But the Uruguayan has been buoyed by the memory of Sebastian Larsson’s winner in last season’s corresponding fixture as part of a four-game winning streak which sealed their unlikely survival bid. Poyet said: “You cannot make (Jermain) Defoe, (Ricky) Alvarez or (Adam) Johnson become robots and do what you want all the time. They have to have the freedom to go forward and express themselves. “I think the mix has to be right – it is not perfect at the moment but we are still working on it.” Sunderland’s win at Old Trafford last year was their first since 1968 and Poyet believes that factor could work to the Black Cats’ advantage as they seek to find the momentum to escape their latest relegation battle. Poyet added: “”It is true that there is something different when you don’t win for years and years in a place and you go there and it looks like it is going to be more difficult than ever, and we did change that. “I think that is going to bring something different to the players – at least those who have been here a while. “But I think it is going to be a totally different game – nothing compared to last year when Ryan Giggs was their caretaker and we were playing for our lives. “Now they are in the process of changing their style of play – for a team that has been playing for 20-plus years in the same way it is going to be a difficult process. “I think people are being a little bit harsh on Manchester United at the moment. They are not as bad as people think because they are in a good position.“ Poyet suffered a blow this week with the news that Italian striker Emanuele Giaccherini is almost certain to miss the remainder of the season after undergoing ankle surgery. But his squad is otherwise nearing full fitness with only Billy Jones and Jack Rodwell struggling for the Old Trafford trip, and more likely to be rested with a view to returning for Tuesday night’s crucial trip to Hull.