Ruben Amorim had a tetchy exchange with a reporter as he refused to explain why he is veering from the 3-4-3 formation he wanted to build his Manchester United side around. The Portuguese was asked three times during Friday's press conference before facing Leeds what he had meant with previous comments about his change of heart. But each time he shied away from giving an answer.Amorim has stuck dogmatically with a 3-4-3 formation ever since taking his first job with Casa Pia in Portugal's lower leagues and has played the same way in the vast majority of matches since becoming United coach, even though it has yielded overall poor results. There had been speculation last month that he was going to start playing a more traditional back four and he did so during the 4-4 thriller against Bournemouth.In his press conference on Christmas Eve before facing Newcastle, Amorim explained why he had had a change of heart and was considering playing a different way as it would take too long and too much money for him to implement his system as he would like. He had said: "I think in the future we can change also, like I was always talking to you guys, the system, we can play a different way. To take more quality from these players, because I have the feeling that if we have to play a perfect 3-4-3, we need to spend a lot of money and we need time. So, I'm starting to understand that is not going to happen, so maybe I have to adapt."The comments caused a stir on social media and in Friday's press conference he was asked to clarify them. But it led to a tense exchange with the reporter asking the questions.Amorim said: "I don't want to talk about that. I just focus on the Leeds game." When asked whether he regretted making the comments, he added: "No, no, no. But I [don’t] want to talk about that."Asked one last time by the same reporter why it had taken him so long to reach that conclusion, he said: "I don't want to talk about that. But you are very smart.." The press officer then swiftly moved on to the next question to change the subject.United fans have shown great patience to Amorim given his dismal record of results but there has been growing criticism against the coach online while supporters at Old Trafford booed the team off the pitch after the 1-1 draw at home to Wolves, who are on the worst run of results in the history of the English top flight and had lost their previous 12 games in all competitions. Gary Neville was among those to question Amorim's substitutes against Newcastle while fans booed when he brought on Leny Yoro and Bendito Mantato in an attempt to win the game against Wolves. The coach, however, defended his decisions even though he admitted that not everyone agreed with them.He added: "I understand the team better than anyone. And sometimes you have the supporters on your decisions. Sometimes you have to do what you think and sometimes it's hard for them to understand. But I know when I look at the pitch, I can understand which player is tired, which player is going to struggle a lot if there is one against one all the time. And I just try to protect the team and just try to win games."Add GOAL.com as a preferred source on Google to see more of our reportingHaving dropped points against a woeful Wolves side, United visit a much-improved Leeds who are unbeaten in their last six games and have soared eight points clear of the relegation zone. Amorim said his side would still be without the injured centre-backs Matthijs de Ligt and Harry Maguire plus midfielders Mason Mount, Kobbie Mainoo and captain Bruno Fernandes. Noussair Mazraoui, Amad Diallo and Bryan Mbeumo are still away at the Africa Cup of Nations.Amorim warned of the danger Leeds can pose with their speed. He said: "They have a lot of pace and sometimes we struggle with pace. We prove that we can win any game in any situation in every context. We will try to do that. We know they change the system; the last game they rotated two players who are usually the starters, Good players, and a good manager."