Westwood was signed during the final week of the summer transfer window, from League One side Crewe, but did not make his full debut until last month.
Lambert said: "I think a lot gets overlooked with Ashley but he has just come in here and has taken to it no problem whatsoever.
"He was captain at Crewe and played a lot of games in men's football before he came here so he knew what it was about.
"I trust people to go and play, to go and give everything they've got and he has not let me down.
"If you look at the stats regarding his passing, they are terrific, something like a 91 per cent success rate and he never gives the ball away. He's been exceptional."