The chairman has backed his side to bounce back at home to Everton this weekend.
The Hammers were beaten 2-0 by the newly promoted Hornets on Saturday afternoon in another disappointing display for them against a side they would expect to beat.
It was an even more disappointing display for the side given they had done so well to defeat Chelsea last time around, although underperforming after big displays is becoming something of a trend for Slaven Bilic’s side.
And Sullivan says he wasn’t surprised by the result as it fits a theory he has about their form but insists that they have still enjoyed a great start to the season.
“I have a theory that if you win big you lose the next game. We won against Arsenal and were then poor against Leicester,” he told whufc.com.
“After our 'big win' over Chelsea, the defeat therefore wasn't such a surprise to me. That said and done, to have 20 points on the board after 11 games is still a great start to the season.”
The West Ham chairman has however backed his side to bounce back when they host Everton next time around.
The game will not be an easy one against the Toffees however, with them having bounced back from back to back defeats to thrash Sunderland 6-2 on Sunday in a highly accomplished performance.
Sullivan though, is hoping that his theory will see the Blues fall to defeat at Upton Park, saying Slaven Bilic and his player will be working hard this week to put things right.
“I know that Slaven and his backroom staff will be working hard with the players this week to put things right,” he added.
“I am now hoping that Everton's big win over Sunderland might see them lose against us next weekend. We will all be looking for a better performance when we return to the Boleyn Ground this weekend.”