City, who played without a centre-forward, left United dizzy with their passing and movement and were 3-0 up after 38 minutes thanks to Bernardo Silva, Riyad Mahrez and an Andreas Pereira own goal.
At that stage United were facing humiliation, but City played with less intensity in the second half and that made for a more even contest. United’s young team played with impressive defiance in the circumstances, and gave themselves an outside chance of a miracle when Marcus Rashford scored in the 70th minute.
United will need to win by at least two goals in the second leg at the Etihad – and that’s just to take the tie to penalties. They won impressively away to City in the Premier League last month, when they led 2-0 for much of the game. But if Pep Guardiola’s team play as they did in the first half here, they will surely go through to meet Leicester or Aston Villa in the final.
Pep’s false front pair. At Barcelona, Pep Guardiola was one of the first managers to successfully use a false nine when he redeployed the right winger Lionel Messi. At Old Trafford he went even further by using two false nines in Kevin De Bruyne and Bernardo Silva. United’s centre back pairing were left marking air as City ran riot.
'I don't feel sorry for United' - Guardiola
MAN OF THE MATCH - Bernardo Silva
He has quietly established himself as one of City’s most reliable big-game players, and he did it again at Old Trafford. Silva opened the scoring with a screamer, made the second for Riyad Mahrez with a delicious through ball and generally gave United a puzzle they struggled to understand, never mind solve.
Manchester United: De Gea 7, Wan-Bissaka 6, Jones 4, Lindelof 5, Williams 7, Pereira 5, Fred 5, James 5, Lingard 3, Rashford 7, Greenwood 7. Subs: Matic 6, Gomes 5, Martial 6.
Manchester City: Bravo 6, Walker 8, Otamendi 6, Fernandinho 8, Mendy 6, Rodri 8, Gundogan 7, Mahrez 9, B Silva 9, De Bruyne 8, Sterling 6.Subs: Jesus 6, Foden 6.
17’ GOAL! Bernardo Silva gives City the lead with a stunning goal! He moved infield from the right, away from Fred, and drove a spectacular shot across goal that beat de Gea and flew in off the underside of the bar. Great goal!
33’ GOAL! Riyad Mahrez makes it two! Bernardo Silva picked up a loose ball just past the halfway line and played a delicious through pass to Mahrez, who danced round the onrushing de Gea to score. City have been majestic.
38’ GOAL! Man Utd 0-3 Man City (Pereira og) This is brutal. City break to devastating effect and take a three-goal lead. Eventually De Bruyne twists Jones inside out on the left of the area and whacks a shot that is saved by de Gea - but the ball rebounds off Pereira and into the net.
69’ De Gea makes a fine save from Mahrez! That could easily have been 4-0. Mahrez teased Williams on the edge of the box, beat him with a step-over and smacked a low right-footed shot that was kicked away by the stretching De Gea.
70’ GOAL! It could have been 4-0; instead it's 3-1. City gave the ball away near the halfway line and United pounced. Greenwood played a nice pass to put Rashford through on Bravo, and he finished emphatically into the bottom corner.
'Pride at stake after worst United showing of season' - Solskjaer
- Manchester City won a cup tie at Old Trafford for the first time in their history.
- United conceded three first-half goals at home for the first time in 23 years.
- Riyad Mahrez scored his first career goal against United.