Van Gaal hails United development
Louis van Gaal has warned Manchester City they will face a completely different United side to the one that wilted in their last derby clash at the Etihad Stadium.
Van Gaal experienced one of the most disappointing results of his reign in November when United lost 1-0 at City thanks to Sergio Aguero's goal.
Without a win in three matches going into the derby, City were there for the taking, but United barely laid a finger on their opponents.
Van Gaal's team registered just two shots on target, Chris Smalling was sent off inside 39 minutes for two needless yellow cards, and United ended the match with Michael Carrick and Paddy McNair at centre-back after Marcos Rojo dislocated his shoulder following a rash sliding tackle.
Five months on, things have improved immensely for Van Gaal. United play with much more confidence and they have rediscovered the killer touch that allowed them to register their fifth straight league win on Saturday against Aston Villa.
"It was another Manchester United, I believe," Van Gaal said when asked to reflect on the 1-0 defeat against Manuel Pellegrini's side.
"That was more in the start of the process and now we are in the end of the process.
"Now we have developed the team.
"I think also the confidence of our players is very high at the moment but also our performances show that so it's not the same Manchester United."
That win proved vital for City. They dropped just four points in the following 10 league matches and were level with leaders Chelsea on New Year's Day.
Now they are below United and nine points behind leaders Chelsea, although they have a chance to make up ground when they face Crystal Palace on Monday.
United, on the other hand, are third in the table having enjoyed a run of five straight wins.
Van Gaal believes United's recent good form could be playing on the minds of the City players when they come to Old Trafford on Sunday.
"Of course it plays a part in the spirit of our opponents and also our players," the United boss said.
"We have more confidence now and when they lose a point then it's also sitting in the minds, so maybe it plays a role but that is dependable of the individual player and I don't know the individual players of Manchester City so well so I cannot judge, but we have a lot of confidence and we haven't lost so many times at home."
Although the victory against Aston Villa - which came courtesy of a Wayne Rooney volley and an Ander Herrera brace - was important, Van Gaal knows the derby will be United's big chance to cement their place in the top four.
"This is the decisive game," he said.
"It's like the game against Liverpool and the game against Chelsea - you have to win these kinds of matches."
If United play anything like they did against Villa, they will stand a good chance of ending their run of four successive derby defeats.
The hosts kept the ball well, enjoying 77 per cent of the possession, and produced three top-quality goals.
Herrera swept in a low half-volley to put United ahead and rounded off the win in injury time with a well-taken strike on the break.
The goal of the game undoubtedly belonged to Rooney though.
The England captain cushioned Angel di Maria's cross with his back to goal and then swept the ball past Brad Guzan on the turn.
"That's Rooney," Van Gaal said with a smile.
The Dutchman praised Di Maria for his impact off the bench, but that does not mean the Argentinian will walk into the team next weekend.
"Now we are winning five games in a row so everybody has to wait for the right moment," Van Gaal said.
Other than Christian Benteke's consolation, Villa offered little on the attack and they are now in serious danger of being sucked back into the relegation zone.
Tim Sherwood is looking for an immediate response when his team host relegation rivals QPR, who hammered West Brom 4-1 on Saturday.
"It's a massive game for us," the Villa boss said.
"They got a good win today. It was a great result for them.
"But we're aiming to put six points between us and them by the end of that game."