Graham Carey scored a goal of the season contender as Lennon's men recorded a 2-0 win in the in the Clydesdale Bank Premier League match at St Mirren Park.
The five changes the Saints boss made to the team that lost to St Johnstone at the weekend paid off as they grabbed a 2-0 lead at the break. Paul McGowan blazed home from the penalty spot after three minutes and Carey's impressive second goal extended their lead on the stroke of half-time.
Lennon said: "I was delighted with the performance, particularly in the first half. A few of the lads came in and did very well and that's what a squad is all about. Those lads have been patient.
"The timing of the two goals was perfect. The penalty set us on our way and some of the football we played was excellent and back to the identity of the stuff we played earlier in the season.
"If Graham's goal had been scored by Gareth Bale it would probably have been spoken about - goals like that deserve to be highlighted - it shows you the type of player and the quality we have."
Hearts manager John McGlynn was disappointed as Hearts fell to their fourth successive league defeat.
The Tynecastle boss felt conceding the first goal after only three minutes proved to be vital and insists his team must starting making a brighter start to matches.
"To lose a goal so early away from home puts you under a bit of pressure and gave them a bit of a lift as they haven't been going too well lately either," said McGlynn.
"The second goal was a fantastic strike and difficult to defend against. I thought we put a lot into the second half, without creating a great deal of clear-cut chances. It was a lot better, however we can't wait until half-time to start playing."