West Ham boss Slaven Bilic has branded the EFL Cup meeting with League Two Accrington as the first of three finals for his side.
The Hammers, already in the bottom three of the Premier League following four defeats from their first five matches, then face crucial home games with Southampton and Middlesbrough.
"Very soon it is that time in the league when you can get in trouble," admitted Bilic.
"We have to act, and very soon you can get out of trouble but it isn't going to happen by default.
"We have to do it.