West Ham’s 3-0 defeat against Southampton on Sunday condemned the Hammers to their worst start to a season since 2002, when they were relegated.

Slaven Bilic’s side were one of last season’s surprise packages, and their seventh-placed finish earned them a place in the Europa League qualifiers.

Now, having since lost five of their opening six Premier League matches, West Ham are surprising people for all the wrong reasons.

Here, we look at five reasons why it is all going wrong for the unhappy Hammers.

1. New stadium

(Adam Davy/PA)

There is a lot of misty-eyed nostalgia surrounding West Ham’s move from Upton Park to the vast former Olympic Stadium and its so-called lack of atmosphere. In fact, the Boleyn Ground could resemble a library at times, just like any other ground in the country.

Furthermore, although it might seem ridiculous, West Ham did lose the occasional game at their old stadium as well. Many teams have taken time to adjust to their new surroundings after switching grounds and West Ham are certainly making it look difficult.

2. New signings

(Matt Dunham/AP)

West Ham brought in 11 new players over the summer but only one of them, Andre Ayew, could be considered a starter in Slaven Bilic’s first-choice line-up – and he was injured half an hour into his debut.

Of the rest, Simone Zaza is struggling to convert his viral video training ground efforts into Premier League points, while Gokhan Tore, Sofiane Feghouli and Arthur Masuaku frankly look out of their depth. Their exit from the Europa League has left the Hammers with a bloated squad full of average players.

3. Injuries

(Andrew Matthews/EMPICS Sport)

New stadium, same old story. While Andy Carroll’s injuries now arrive as surely as day follows night, the loss of Ayew and Aaron Cresswell – as well as Dimitri Payet and Manuel Lanzini earlier in the season – has taken its toll.

Diafra Sakho’s move to West Brom fell through due to concerns over his fitness so he remains at the club, and you guessed it: he’s injured as well.

4. Defending

(Matt Dunham/AP)

The Hammers have conceded 14 goals in their last four Premier League matches and have looked a shambles at the back. Time seems to be catching up with James Collins, while Winston Reid and Angelo Ogbonna have become error-prone, and Bilic does not seem to trust talented teenager Reece Oxford.

All of which makes the sale of James Tomkins to rivals Crystal Palace utterly baffling. Thankfully the experiment of playing Michail Antonio at right-back seems to be over.

5. Maybe they’re not actually that good

(Nigel French/EMPICS Sport)

At the end of last season the Hammers lost 4-1 at home to Swansea and slumped to a 2-1 defeat at Stoke on the final day of the season to drop to seventh. The memorable win over Manchester United in the last game at Upton Park, and the after-party that more accurately resembled a filibuster, may just have papered over the cracks appearing in a team already on the slide.

Payet took the Premier League by storm last season but even he can’t win every game on his own. Perhaps teams are finding out that if you keep him quiet, there is not too much else to worry about.