Jonny Evans believes Manchester United's humiliation at the hands of Manchester City has served as the inspiration for the former's sensational recent run of form.
United were hammered 6-1 by their cross-town rivals at Old Trafford in October as City established themselves as favourites for the Barclays Premier League title.
However, since then, United have taken 25 points from a possible 27 in the league, and have kept seven clean sheets on the way.
The reigning champions are now level with points with City, and 10 goals in their last two games has seen the goal difference closed to a gap of only five.
And Evans says the defeat to City made United address their mentality - and it has worked for the best.
"At the start of the season we were playing this open, attacking football," the centre-back told manutd.com.
"It seemed like it didn't matter if somebody scored two goals against us because we'd go out and score three.
"It's hard to maintain that throughout a season, though."
He added: "Since the Manchester City game we've defended better, but it wasn't a case that we all sat down and discussed what needed to be done - it was just a realisation in people's minds that we had to work that little bit harder.
"I think sometimes if you start to find games easy you can take your foot off the pedal and your eye off the ball.
"Everybody knows in themselves what we had to do and we're working hard for each other and making it hard for other teams to beat us."