West Ham made heavy weather of the opening match of their latest European adventure as they had to come from behind to beat Serbian minnows Backa Topola 3-1.

Headers from £38million summer signing Mohammed Kudus and substitute Tomas Soucek, both from James Ward-Prowse corners, got the Hammers’ Europa League campaign off to a winning start on a stormy Stratford night.

East London was hit by torrential rain before kick-off with water cascading through the roof onto the concourses at London Stadium.

The floodgates failed to open on the pitch in the first half, however, despite West Ham being in the rare position of dominating possession on the soggy surface.

The Hammers had 78 per cent possession, which was the exact opposite of their stats during the recent smash-and-grab win at Brighton.

But boss David Moyes got a taste of his own medicine when Angelo Ogbonna’s mistake gifted TSC, making their debut in the group stages of a European competition, a shock lead after half-time.

Until then it had been one-way traffic after Ward-Prowse had an early free-kick deflected inches over the crossbar.

Danny Ings, making his first start of the season, saw his swerving effort punched away by Serbian keeper Nikola Simic, who also denied Thilo Kehrer after Aaron Cresswell’s low cross found him at the far post.

Lucas Paqueta’s drive then forced another unorthodox save from Simic and when Pablo Fornals lifted the loose ball back into the box, Kudus planted his header over the top.

But for all West Ham’s dominance there was still a hairy moment when a corner from Petar Stanic was flicked on by Sasa Jovanovic and bounced right across the six-yard box.

The underdogs were enthusiastically cheered from the pitch at half-time by the 75-or-so Serbian fans who had made the 2,000km journey.

And those away supporters were in dreamland two minutes into the second half after Ogbonna dawdled on the halfway line, allowing Stanic to nick the ball, race clear and fire past Lukasz Fabianski.

But the Hammers, whose last European outing was their triumphant Europa Conference League final win over Fiorentina in June, hit back in the 66th minute, albeit in fortunate fashion as Said Benrahma’s cross was turned in at the far post by TSC defender Nemanja Petrovic.

The lively Kudus did get his goal four minutes later and Soucek headed in the third from another Ward-Prowse delivery – giving the former Southampton midfielder a fifth assist of the season – to finally ease West Ham nerves.