Michail Antonio and Declan Rice were on target as West Ham claimed a flawless 2-0 victory at Dinamo Zagreb in their Europa League opener.
On what was their first appearance in a major UEFA competition since 2006/07, and arguably their toughest Group H assignment, it was like the Hammers had never been away from the European stage as they produced an accomplished performance in the Croatian capital.
Talisman Antonio set West Ham on their way inside 21 minutes, pouncing on a loose back pass to score the Hammers' first major European goal since 1999, before captain Rice sealed the victory with a superb solo run and finish five minutes into the second half.
Underpinning West Ham's superiority in attack was an assured defensive performance, anchored by debutant Kurt Zouma, as a clean sheet guided the Hammers to an away win and into early control of the group.
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Manager David Moyes admitted beforehand that the trip to the Croatian league and cup winners might be their toughest assignment in Group H.
After all, Dinamo had reached the quarter-finals last season while accounting for Tottenham 3-0 along their way.
As such Moyes named a strong line-up despite making five changes from the weekend draw at Southampton, with Tomas Soucek and £30m new signing Kurt Zouma joining Rice and Antonio in the starting XI at the Maksimir Stadium.
His side opened the scoring in the 22nd minute thanks to a shocking backpass which will give Jesse Lingard flashbacks to his error earlier this week.
Kevin Theophile-Catherine was the guilty party with Antonio onto the loose ball like a flash.
He poked the ball past stranded goalkeeper Dominik Livakovic and from a tight angle rolled it into an empty net.
Ryan Fredericks should have made it two moments later after he was sent through by Antonio's clever flick, but Livakovic stood up well and saved with his feet.
Another summer signing, Nikola Vlasic, back in his home country, could have added a second before half-time but saw one shot blocked in a crowded penalty area and flashed another just wide.
Instead Rice doubled the lead with a maiden European goal following a trademark surging run five minutes into the second half.
Rice burst through a challenge on the halfway line and charged forward before lashing a shot through Livakovic's legs.
Pablo Fornals saw a late effort kept out by Livakovic, while Hammers goalkeeper Lukasz Fabianski barely had a shot to save in an impressive opening to West Ham's European campaign.
What the manager said…
West Ham manager David Moyes: "I was really pleased with the way the players played. Zagreb have a really good history in European football so I knew it was going to be a tough game and the players were made aware of that.
"It's something new for us, certainly to someone like Declan Rice who's played for his country but not in Europe for his club, so it's something he's going to have to get used to as it is for most of the players here.
"I'm really excited about the prospect of slightly not knowing how good they could be. We brought in some new players tonight and didn't look any the worse for it.
"Bigger challenges will come and my target is still to still be in Europe after Christmas, when other teams come in. It's only one game, but the players are in a good place."
Analysis: Hammers can prepare for Man Utd test on a high
Former West Ham striker Marlon Harewood to Sky Sports:
"What a night for West Ham and the performance they put on tonight was absolutely fantastic. Throughout the team, they've been solid. From the first minute they've been on the front foot and have not given Dinamo any chances until the first goal from Antonio went in.
"The hosts then had to step things up, but, within five minutes of the restart, West Ham doubled their lead. It has been a very solid evening for the Hammers and a performance tonight means they can go into the weekend game with Manchester United on a high.
"They'll miss the suspended Antonio but I'm sure David Moyes will have a plan."
Live Renault Super Sunday
West Ham resume their Premier League campaign against Manchester United on Sunday, live on Sky Sports Premier League from 1pm, with kick-off at 2pm. Their next Europa League game is at home to Rapid Vienna on September 30.