Guzan thinks there has been a noticable change in team spirit at Villa during the close season, which will help them come through stern tests as the campaign progresses.
He told The Mirror: "I think it's massive and evident to see the change. Do I think we are in a better position to compete and go and win games? Yes. Our performances over the last week against top teams are a credit to what the manager and the coaching staff have done in terms of changes.
"Not just on the pitch but the atmosphere and camaraderie in the dressing room and at the training ground. That is important because when you go through difficult times on the pitch you have to be willing to fight for each other.
"It wasn't our best start to this game but in the second half there was only one team on the pitch. We were unfortunate not to get something from the game. With the players we have and the atmosphere that has been created we want to put together performances we are proud of."
Lambert's side turn their attention to the League Cup on Wednesday night, when Rotherham United visit Villa Park.