Juan Mata scored to steer Manchester United into the League Cup quarter-finals with a 1-0 win over cross-town rivals Manchester City as Jose Mourinho got one over old adversary Pep Guardiola.
Mata rifled in a low finish past City keeper Willy Caballero early in the second half at Old Trafford on a night of few chances but plenty of derby fervour as United boss Mourinho won the tactical battle against Guardiola's much-changed City side.
West Ham United also moved into the last eight after they overcame Chelsea 2-1 in a London derby spoiled by ugly scenes of fan violence at the end of the game.
A superb first-half header from Cheikhou Kouyate and Edimilson Fernandes's low finish put West Ham 2-0 up at the London Stadium, before Gary Cahill swept home a consolation from close range in injury time.
Southampton heaped more misery on struggling Sunderland as record signing Sofiane Boufal scored from long range in the second half to secure a 1-0 victory.