The Blues were given a reality check after losing at the Hammers, but they have responded since that game with two consecutive wins.
They are third in the Premier League and hope to maintain a top four position when the season concludes.
"That West Ham game just gave us that little boost and say, 'hey, we've got to be focused every single game,' and we've got to be ready to go now and get results," Pulisic told Sky Sports.
"But there's a lot of positivity.
"Finishing in that third spot is where we want to be, and we want to go on and win the FA Cup."