Scott McTominay scored in extra time to send Manchester United into the quarter-finals after a flat 90 minutes against West Ham.
On a bitterly cold night at Old Trafford, the hosts came closest to breaking the deadlock inside 90 minutes when Lukasz Fabianski reacted quickly to turn the ball on to a post after Victor Lindelof’s header had taken a huge deflection off Craig Dawson.
But McTominay had the final word. Following a break that took them from one penalty area to the other, Marcus Rashford – on his 250th United appearance – flicked a delicate pass into McTominay’s path with the outside of his foot and the Scotland midfielder’s first-time finish flew low into the net.
It was another disappointing Old Trafford night for former Manchester United manager David Moyes. Other than during his own ill-fated eight months in charge, it is a ground he has never won at, either with Everton, Sunderland or West Ham.
Before kick-off, the Scot had a good chat with current boss Ole Gunnar Solskjaer and doubtless wished he had been granted the same time afforded to the Norwegian, who is attempting to win a trophy after losing four successive semi-finals.
Moyes’ hopes of stopping the hosts in their tracks were badly affected by injuries that now threaten to derail what so far has been an excellent season.
The sight of Angelo Ogbonna hobbling down the tunnel with his left boot removed, after being stood on by Martial, did not look great, and the manner of Diop’s exit suggests we will be without two central defenders for Monday’s encounter with Sheffield United.
With our only orthodox striker, Michail Antonio, also missing, we never really gained any momentum and were not helped by yet another injury – this time to Antonio’s replacement Andriy Yarmolenko – early in the second half.
Said Benrahma had our only effort on target, but even if he had beaten Dean Henderson with a close-range header at the end of extra time, it would almost certainly have been disallowed for offside.
This game will also have a place in football history after Diop became the sport’s first concussion substitute in England.
The French defender was introduced as a replacement himself after Ogbonna was forced off with an ankle injury when he was caught on the follow through by Martial.
Diop clashed heads with his compatriot as the pair rose to compete for a header at a corner.
Both players received treatment and continued to half-time. But after a further examination in the dressing room, in line with the adopted protocols, Diop was replaced by Fredericks, with the visitors reverting to a three-man defence.