Louis van Gaal believes Manchester United can still catch second-placed Manchester City and insists he is focusing on overhauling the teams above them, not worrying about the ones beneath them.
The United manager has admitted it is imperative the former Premier League champions return to the Champions League at the first time of asking and accepted it would be a major blow if they fail to do so.
United have been in the Champions League places for most of the last four months but face the prospect of dropping out of the top four if they lose to Tottenham on Sunday and then Liverpool win at Swansea on Monday.
And Van Gaal feels United face a defining period as they meet top-six rivals Spurs, Liverpool, Manchester City and Chelsea in their next five games.
But the former Barcelona and Bayern Munich manager, who has confirmed that Robin van Persie will miss the games against Tottenham and Liverpool but should return after the international break, insists he is optimistic when he looks at the league table.
"Manchester United has to be one of the teams who has to play in the Champions League," he said in a news conference. "We have seen that this year. It is not good. Surely when it is the second year. But it is always possible because you never win every game and there are a lot of clubs who are going for it.
"They are very decisive, the coming matches. Of course, after a defeat at home [against Arsenal in the FA Cup], it is also [important] to see the reaction of the team. We play against a very good team in Tottenham. We can see already the next match. But then, still, we have to continue. We are so close with a lot of clubs. We can be second or third."
United have used a back three and a back four, one striker and two and a midfield diamond among Van Gaal's many tactical changes this season.
The 63-year-old believes he should not be branded indecisive for changing formations so frequently and argues he is trying to school his players to switch seamlessly between systems.
"I don't think that is fair," he said. "I don't think a lot of trainer-coaches are doing that. There was also a lot of education we had to do to play the system and the players have to work very hard.
"But that is also part of the philosophy. The philosophy is more important than the system or the shape. It is also a step in the process.
"When you are adapted to use your brain for everything you do, then it is more difficult. But at the end, you have to do it automatically. Then we are where we want to be."
Van Gaal, who had said he was likely to use Wayne Rooney in midfield, insisted he has not performed a U-turn after restoring the captain to the United forward line.
"I have said that Rooney is a striker who can also play in midfield," he said. "He has shown that. Now, in this moment, I think it is better to play Rooney [in attack].
"It depends on what I see, what the game plan of my opponent and then also from the suspensions I have or the injured players, the composition of the team."
Tottenham were interested in appointing Van Gaal manager last year and eventually plumped for Mauricio Pochettino but the Dutchman insists that is ancient history.
"It is not interesting anymore," he added. "It is the past and we live in the present."