Saïd Benrahma (27) could be accused of being wasteful in the reverse fixture, but the Algerian quickly atoned for that here, guiding a precise free-kick beyond Hendrik Van Crombrugge’s reach for his second European goal of the season.
Jarrod Bowen (25) was tasked with leading the line, and after offering a suggestion of his threat via an offside snapshot, the England international doubled the Hammers’ lead.
Emerson Palmieri drove forward down the left before pulling back to Bowen, who rifled into the top corner from the edge of the box. The 25-year-old was then unable to convert Aaron Cresswell’s pull-back before a Fábio Silva-led counter-attack ended with Sebastiano Esposito testing Alphonse Areola (29).
Having largely controlled the first period, West Ham remained on top after the break, almost finding a third goal when they carved through Anderlecht, but HT substitute Pablo Fornals saw his close-range effort blocked.
David Moyes made further changes just after the hour mark, introducing Declan Rice (23) and Gianluca Scamacca (23), as Bowen left the field now tied as West Ham’s all-time top European goalscorer with six goals to his name.
Injuries to centre-backs Angelo Ogbonna and Craig Dawson looked to be the only negative from a Hammers’ point of view, but an unlikely late penalty conceded by Ben Johnson allowed Esposito to haul his side back into the contest.
Nevertheless, West Ham did enough to see out victory, leaving them out of Anderlecht’s reach thanks to an eight-point gap.
Meanwhile, the Belgian side extend their unwanted record on English soil, having failed to win a UEFA European away game in 90 minutes on 17 occasions, losing 15 of those.
Flashscore Man of the Match: Saïd Benrahma (West Ham United)