Juan Mata described Manchester United's 4-2 derby victory over Manchester City as "massive," with the result giving Louis van Gaal's side a four-point lead over their neighbours.
United had lost their last four matches against City, but goals from Ashley Young, Marouane Fellaini, Mata and Chris Smalling gave them their biggest derby win in six years.
Sergio Aguero opened the scoring and also netted late on for his 100th City goal, but United were by far the better team and tightened their grip on third place in the Premier League.
"The first 10 or 15 minutes they were brilliant and played well, but after that the team showed character and we came back,'' Mata told Sky Sports 1.
"It's a massive win for us, it's a great result and everyone at United is happy. The atmosphere was crazy -- it is something we will never forget.
"You could tell how important it was for the fans, but we still have six games to go and we have to keep going.
"It's a big win and a boost of confidence, but Arsenal are doing great and I'm sure City and Liverpool will fight to the end, so we have to fight to the last minute."
Meanwhile, United boss Louis van Gaal said he hoped Michael Carrick would not be a doubt for Manchester United's trip to league leaders Chelsea on Saturday.
Carrick left United down to 10 men for the closing moments after limping off with a calf problem, with the manager having used all his substitutes.
He will be assessed on Monday, and Van Gaal said: "He was wise to step off, but we have to wait and see tomorrow.
"He had a stiff calf and he is a very experienced player so he asked to leave the pitch. I said: 'Okay.'"
Van Gaal added: "It was an error from me that I give too many minutes to my substitutes, because it is not so wise to change all your three possibilities."
Information from ESPN FC correspondent Richard Jolly was used in this report.