The Hammers slumped to a fifth loss in their opening six Premier League matches, going down to a Saints team who had previously scored just four goals in their opening five games themselves.
In truth, West Ham looked like a team lacking belief in the final third, while defensive errors were again capitalised upon by their opponents, as they had been in 4-2 defeats by Watford and West Bromwich Albion in the previous two league matches.
“We are not the first or the last team who has been in this situation in the Premier League and most of it is about confidence, but the Club has the same players and the same manager who did good things last year,” said Bilic.
“Eighty per cent of the team is the same, and of course we can talk about confidence and urge them to be confident, but you need one or two good results to get that confidence and that’s not happening at the moment.
“We are working hard in training, analysing and talking and it’s good until the game comes and someone punches us in the face, then we have a problem.”
Having conceded four goals in each of their previous two league games, Bilic set his team up to be more disciplined and compact, and that was the case for much of the first half, only for Charlie Austin to convert their first chance a minute before half-time from Ryan Bertrand’s low cross.
West Ham threw caution to the wind after the break, but found Claude Puel’s well-organised Saints a difficult team to break down.
While the Hammers found it hard to fashion clear-cut chances, Southampton took advantage of a defensive lapse to double their lead when Dusan Tadic rounded Adrian – by far the busier of the two goalkeepers – to score.
Then, in added time, substitute James Ward-Prowse completed a miserable afternoon by converting Steven Davis’s cutback.
“They deserved it. We started well, with people behind the ball and closing the opponent down. We were defending well as a team, considering we had conceded eight goals in the last couple of games.
“In the first half, in that part of the game we were good, we were compact and everything. But we weren’t happy with the way we were with the ball, especially in the last third of the pitch, where we didn’t penetrate enough.
“The first mission was to be better defensively, but that should be the mission in every game. In the first half we were solid and regrouped well behind the ball, but we’re at home and need points and we were not happy with the way we attacked when we had the ball.
“We were a little bit unlucky in the first half, because they didn’t deserve to be one up in my opinion.
“In the second half we were trying to get back in the game, but we made one big mistake and they took advantage of it.
“After it went to 2-0, we tried to put them under pressure and had a couple of chances which were on target, but they were always very quick in the moment of transition and had a few chances as well."