Strikes from Charlie Mulgrew, Anthony Stokes and a double from Kris Commons in Paisley extended Celtic's lead at the top of the table to 14 points.
"We felt at half time if we got one goal, we would go on to dominate the game," said Lennon.
"And that's how it panned out. It was a magnificent team performance and another clean sheet."
Highlights - St Mirren 0-4 Celtic
The victory extended Celtic's run of games without conceding a goal to eight in domestic competitions and increased their points tally to 54 ahead of second-placed Motherwell.
Lennon insisted that the goal tally could have been higher, with two chances denied in the second half by the St Mirren woodwork, but could not find fault with the performance of his players.
"I thought we played well in the first half, but I thought we were exceptional from start to finish," said Lennon.
"We could have been two up, but for the inside of the post. I can't ask for any more of them, they're doing the club really proud.
"You have to have faith in the players. I felt we could have kept the ball in the final third a bit better at times.
"We did that better in the second half and we started to stretch St Mirren and they found it difficult to live with us after that."
As the second half of the season progresses at pace, thoughts now turn to potential candidates for player of the year, and Lennon insisted he has several high performers in his squad who could make the grade.
"I'd say we'd have a few contenders," said Lennon. "Virgil van Dijk, Efe Ambrose and Scott Brown - who doesn't always get all the plaudits - has had a brilliant season.
"We have four or five in the mix, and it's a bit early, but they're playing at the top of their game."
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