Despite juggling a Premier League relegation battle and the return of European competition next week, Moyes named close to his strongest possible side for the trip north and at one stage looked on course to be rewarded with a place in the quarter-finals.
The Hammers were the better side during the first half and led through Said Benrahma’s strike soon after the break, having already spurned several opportunities to open the scoring.
However, the home side hit back with Nayef Aguerd’s own goal before late strikes from Alejandro Garnacho and Fred completed the comeback, both goals coming after the Irons had conceded cheap possession at the back.
“We had great opportunity to get through tonight. We played well and we blew it in my eyes,” Moyes said. “We could have got a second goal and when we didn’t we had to make sure we didn’t concede. We ended up giving away two ridiculous goals.
“I thought we had a great opportunity to knock United out and for long periods we played well enough. We just didn’t get over the final bit you need to. We didn’t do the basics well enough, some real simple things.”