Darren Bent reportedly did not know that he was not selected to start last Sunday's 1-1 draw with West Bromwich Albion, but Lambert has used the fact that he scored from the bench as justification for his methods.
"It's just something I've always done," the Daily Star quotes Lambert as saying. "If you tell someone they're going to play two days before the game, I think they might take their foot off the pedal a little bit.
"There's nothing better than sitting on a knife-edge at times.
"To be fair to Darren, he came on and it was an absolutely brilliant finish. He is a natural goalscorer."
Aston Villa travel to White Hart Lane to face Tottenham Hotspur this afternoon.