Boro went down 3-0 on Westley's return to Deepdale, where he had an ill-fated spell in charge last year, at the weekend.
But the Boro chief feels his new-look side will be in far better shape as the season progresses and already has his eye on a spot of revenge.
"The mentality of the team probably wasn't quite strong enough when we suffered the body blow of the second goal," he said.
"You have to have a mentality to overcome setbacks and I think the mentality of the team probably isn't at a level yet, with the newness and the youth, to recover from that blow.
"But on the whole there were some positive signs and I really would take us to win the reverse fixture."