Manchester City gained revenge for derby defeat to Manchester United last month by teaching their city rivals a lesson in a 3-1 League Cup semi-final, first-leg win at Old Trafford on Tuesday.
The holders were rampant before the break as Bernardo Silva's wonder strike, Riyad Mahrez's cool finish and an own goal from Andreas Pereira put City well on course for a third straight League Cup final.
United's captain for the evening Marcus Rashford restored some pride for the hosts to reduce the deficit 20 minutes from time, but they face a huge task when the sides meet again for the second leg on January 29.
Ole Gunnar Solskjaer's men had torn City apart on the counter-attack to shock the Premier League champions on home soil a month ago.
That league defeat allied to another loss at Wolves over the festive season realistically ended City's hopes of catching runaway Premier League leaders Liverpool, leaving Pep Guardiola's men to focus on the domestic cups and Champions League.
Guardiola showed his intent by naming a strong team but without a natural striker as Sergio Aguero and Gabriel Jesus were left on the bench. The fluid front four of Silva, Mahrez, Raheem Sterling and Kevin de Bruyne were too fleet of foot and thought for a United defence without the injured Harry Maguire.
An extra midfielder also helped City dominate possession and nullify United counter-attacks.
City got their reward with a sumptuous strike from Silva to open the floodgates.
The Portuguese international has struggled to reach the heights of a brilliant campaign as City won a domestic treble last season, but was back to his best as he smashed a shot into the top corner from outside the box.
Silva turned creator for City's second on 33 minutes as one pass split the United defence and Mahrez raced in behind Victor Lindelof before rounding David de Gea to slot into an empty net.
Five minutes later it was 3-0 as De Bruyne left Phil Jones flat on the ground before his powerful shot was parried by De Gea into the path of the unfortunate Pereira, who could only turn the ball into his own net.
Only De Gea's brilliance and the profligacy of Sterling prevented the scoreline becoming even more embarrassing for Solskjaer before half-time.
The Spanish goalkeeper spread himself to make a magnificent save from Silva before Sterling failed to turn home Kyle Walker's inviting cross as his run without a goal against United stretched to 18 games.
City eased up after the break but should still have extended their lead when De Gea saved well with his legs from Mahrez.
Moments later, United grabbed a lifeline when they finally caught the visitors cold on the break as Mason Greenwood teed up Rashford to calmly slot into the far corner for his 17th goal of the season.
But there was no late rally from the Red Devils to further cut City's advantage as the blue side of Manchester celebrated a third straight win at Old Trafford and a fourth in five derbies on the road since Guardiola took charge.
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