The Hammers will head into the Premier League game at the Stadium of Light on the back of a 2-2 draw with Norwich City at home.
Slaven Bilic’s side will be favourites to win against Sunderland as they have a better team and have also made a much better start to the season.
The Black Cats are at the foot of the Premier League table at the moment, but West Ham co-owner Sullivan has warned the players against becoming overconfident.
“I just hope we’re not too overconfident going to Sunderland on Saturday,” Sullivan told West Ham’s official website.
“We saw what happened with Chelsea when only two late goals got them a point at Newcastle.
“I’m sure Chelsea will have gone there thinking they would win comfortably and that certainly was not the case.”
Chelsea were favourites to win against struggling Newcastle United at St. James’ Park in the Premier League on Saturday evening, but they had to settle for a 2-2 draw.
Sullivan makes a good and valid point about West Ham players not getting complacent against the Black Cats.
The Sunderland players are under huge pressure, and they will be determined to win their first Premier League game of the season.