The Hammers made heavy weather of the opening match of their latest European adventure on a stormy night in Stratford, but headers from £38million summer signing Kudus and substitute Tomas Soucek got the Hammers off to a winning start.
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, and they fell behind after a mistake by Angelo Ogbonna.
“Tonight I thought we did enough to win although I didn’t think we were great in a lot of things we did,” said Moyes.
“The goal was probably our own doing but I didn’t fear the worst. It was a game where we had the lot of the ball and gave us a chance to see if we could do what teams have done to us lately.
“The mistake changed the game – but it also made us more determined.
“Kudus I thought started really brightly and came up with an important goal when I couldn’t really see where we would get one from.”
The Hammers had 78 per cent possession in the first half, which was the exact opposite of their stats during the recent smash-and-grab win at Brighton.
But Moyes got a taste of his own medicine when Ogbonna dawdled on the halfway line and Petar Sanic raced clear to give the Serbians a shock lead.
However 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.
Kudus got his goal four minutes later and Soucek headed the third – with both coming from James Ward-Prowse corners – to finally ease West Ham nerves.
TSC coach Zarko Lazetic said: “We are disappointed and a little bit angry. We respect the other team, but we felt we definitely had an opportunity.
“Our tactic was to come and win and we feel sorry it didn’t happen.”