Gianluca Scamacca scored his first West Ham goal on Thursday to help secure a 3-1 win over Danish minnows Viborg in the Europa Conference League play-offs.
West Ham, who made the Europa League semi-finals last season, went into the game after back-to-back losses in the Premier League to Manchester City and Nottingham Forest.
But Italian international Scamacca, signed for o30 million from Sassuolo, eased the nerves by finding the target in the 23rd minute after being teed up by another new signing, Maxwel Cornet.
Jarrod Bowen added a second in the 64th minute before Viborg pulled one back through Jakob Bonde five minutes later.
Twelve minutes from time, substitute Michail Antonio scored a third for West Ham to put the Londoners on course for a place in the group stage.
"Gianluca's probably super pleased and I'm equally as pleased," said West Ham assistant boss Billy McKinlay who was standing in for suspended manager David Moyes.
"Strikers are judged by goals so to get off the mark quickly is big and there's plenty more to come from him."
Villarreal, who were Europa League champions in 2021, overcame an early shock to defeat Hajduk Split 4-2.
Stipe Biuk gave Hajduk a second-minute lead but the Spanish side quickly recovered and were 4-1 ahead by the break.
Jose Luis Morales, with a brace, a Marko Livaja own goal and a Gerard Moreno strike in first-half stoppage time put Villarreal in charge.
A Marco Fossati penalty five minutes from time, however, gave Hajduk a glimmer of hope of overturning the deficit in next week's second leg.
Anderlecht, 32-time Belgian champions, came away from Young Boys in Switzerland with a 1-0 win secured by a Hannes Delcroix goal just before the hour mark.
Former Arsenal star Mesut Ozil was left on the bench as his Turkish side Basaksehir were held 1-1 by Antwerp in Istanbul.
Cologne, third in the Bundesliga after two games, lost 2-1 at home to Fehervar of Hungary.