Albion are out of the Carabao Cup after a clinical Manchester United scored three goals for the second time in four days at the Amex to move into the quarter-finals.
Scott McTominay’s header broke the deadlock just before half-time and Juan Mata and substitute Paul Pogba scored in the last 17 minutes to give the scoreline a flattering look.
Graham Potter’s team played some excellent football at times and carved out decent chances, the pick of them midway through the second half when Leandro Trossard was brilliantly denied by Dean Henderson.
Albion made three changes to the side which had beaten Preston in the third-round last week with Lewis Dunk, Ben White and Jayson Molumby all coming into the team.
After some tentative early sparring on a pitch slickened by persistent rain United created the first opening in the 17th minute. Brandon Williams picked out Juan Mata and he threaded a dangerous ball to Odion Ighalo, who took it round Jason Steele but the angle was too tight and his shot hit the side netting.
But after that scare Albion dominated possession and Alireza Jahanbakhsh nearly added to his goals in each of the two previous rounds. Bernardo’s pass found him in space in the D on 26 minutes for a left-footed strike well held by Dean Henderson. And then, after Alexis Mac Allister had darted into space but fired over when off balance, Jahanbakhsh had another good opportunity four minutes before the break.
Pascal Gross threaded a great ball down the right and the Iran international would have been disappointed not to have hit the target from a good position ten yards out.
But having been on top, Albion fell behind in the 44th minute and, as they had on Saturday, United profited from a poorly defended set piece. Dan Burn’s foul on Mata, which saw his name go into the referee's book, earned United a free kick on the right. Mata whipped it in and McTominay had a free run and free header at the far post which he thundered past a helpless Jason Steele.
Neal Maupay and Trossard were brought on early in the second half with Maupay replacing Jahanbakhsh after he appeared to have hurt his knee and limped off.
And Trossard had a great chance to equalise in the 68th minute when he was denied by a brilliant save from Henderson. Jayson Molumby did terrifically to win the ball in midfield and find Gross whose cross picked out Trossard on the penalty spot. The Belgian struck it first time but Henderson plunged to his left to turn it round the post.
It was to prove a costly miss with United doubling their advantage five minutes later when van de Beek’s back-heel set up Mata for a simple right-foot finish.
Substitute Paul Pogba embellished the winning margin with ten minutes to go, his free kick from 20-yards out taking a big deflection off Joel Veltman and going in off the inside of the post.
The day after he was called into the Republic of Ireland senior squad for the second time, Jayson Molmuby produced an eye-catching midfield display full of running, crisp passing and sharp tackling. Molumby was on his backside but still managed to dispossess Victor Lindelof to help set up Albion’s best chance midway through the second half.
There wasn’t quite the same sense of injustice Albion had felt on Saturday after United pinched the Premier League points with a goal in the 100th minute and a three-goal winning margin flattered the visitors, but United were better where it mattered most in front of goal.
Albion: Steele; White, Dunk, Burn; Veltman, Molumby (Sanders 81), Gross, Bernardo; Jahanbakhsh (Maupay 53), Mac Allister; Gyokeres (Trossard 63).
Unused subs: Sanchez, Cochrane, Roberts, Jenks.