WEST HAM slipped to their first European defeat of the season as David Moyes rang the changes to save his stars for the domestic battle for the top four.
Moyes threw in five players from his under-23s side as Declan Rice, Tomas Soucek and Co were given the night off ahead of the trip to Burnley on Sunday.
Mislav Orsic opened the scoring for the visitors at London StadiumCredit: Reuters
And though the kids gave a decent account of themselves they were unable to recover from the shock of falling behind in the third minute.
It was only down to the excellent displays his side had produced earlier in the competition that Moyes was able to make the changes he did.
With qualification as winners of Group H assured, and a place in the last 16 the reward, this was little more than a second team game for the Hammers.
Of course it meant so much for the graduates from the academy to get the chance to shine, but for Moyes it was a case of giving his senior stars a rest.
The entire back four averaged 19-and-a-half years of age, so Dinamo were always going to be targeting them as they sought the point they needed to qualify for the play-offs.
And the game was barely two minutes old before the Croatians opened the scoring, though it was one of West Ham’s senior players at fault rather than any of the kids.
There seemed little danger when Mislav Orsic collected the ball out on the left touchline, but instead of closing him down Andriy Yarmolenko stood motionless, allowing the forward to step inside and dispatch a dipping shot into the top corner.
The lack of urgency from the Ukrainian summed up his display throughout the remainder of the first half, doing nothing to suggest he should be knocking on the door for a first team chance.
Harrison Ashby, in contrast, rose to the occasion at right back as he also linked up going forward and was the source of most of the London club’s attacking threat before half-time.
The 20-year-old linked up well with Mark Noble to whip in a cross which 17-year-old striker Sonny Perkins headed over on his first senior start.
One player not wasting his opportunity to impress was keeper Alphonse Areola as he looks to try and dislodge Lukasz Fabianski from the number one sport in the Premier League team.
And the Frenchman again did his cause no harm with a string of sharps stops, not least flinging himself to his left to beat away another Orsic effort just before the hour.
The Hammers actually grew into the game as the game wore on as they started to get comfortable with the level of the game.
But lacking the direct threat of the likes of Jarrod Bowen and Michail Antonio, they lacked the creative guile needed to open up the Zagreb defence.
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