Despite Villa's sluggish start to the season, including a 4-1 drubbing at Southampton last Saturday, the Baggies' manager believes their rivals may have turned a corner following their midweek win over Manchester City in the League Cup.
"They've had enough decent results to show what Paul [Lambert] is trying to do there is starting to work," Clarke told reporters.
|9/1||West Brom are 9/1 with bet365 to come from behind to beat Aston Villa on Sunday|
"Their trend is upwards. I've watched a few of their videos leading into this match and you can see the team is starting to play the way Paul would like them to play.
"It is going to start frantic, it is going to be passionate, the crowd will be really involved. It is important for the players to have a cool mind. You have to be passionate, put your foot in and make the tackles.
"But at the same time you have to have a cold mind and be ready to play the football.
"Probably the first team to put their foot on the ball and make some passes will be the team that gets the best start to the game."