Peter Pawlett struck five minutes from time to cancel out Steven Thompson's 54th-minute opener and deny Saints their first Scottish Premiership victory of the season.
St Mirren have now picked up only two points from their first seven league games this term, but Lennon took encouragement from an improved performance.
He said: "It's a small step for us, that's all it is. There is still a long way for us to go. But if we continue to give that application, not just on match-days but on a daily basis, then we'll do well.
"I'm a big believer that if you're faithful to the small things you'll be rewarded in the big things."
Hearts remain bottom of the table as they bid to claw back their 15-point deduction, and Lennon takes his side to Tynecastle for a crucial clash at the weekend.
Lennon added: "I was absolutely delighted with the commitment, the desire, the hunger and the passion.
"I asked the players to leave everything on that pitch tonight and have no regrets and they certainly did that. That level of commitment has got to come first and foremost before any ability.
"We know we've got a name for ourselves that we like to go and pass the ball and we are still a million miles away from where we want to be.
"But it just shows you, with hunger and application, even when you are not at your best, you can still be impressive. You can still pick up points along the way."
The draw ended Aberdeen's three-match winning streak, but they are now unbeaten in six games and two points adrift of third-place Motherwell.
Boss Derek McInnes said: "The positives to take from it are, on a night when we haven't been at our best, we have still managed to take something from the game.
"Once we got the equaliser, the momentum was with us and our biggest enemy at that point was always going to be the clock.
"For us, we never reached the levels tonight that we have shown. There was an opposition there fighting and scrapping for everything to deny you the chance to go and play.
"We didn't move the ball with enough tempo in the first half and we didn't ask enough questions of the goalkeeper. St Mirren, to their credit, worked extremely hard to deny us.
"We are disappointed with the goal we lost because we had two or three opportunities to deal with it and clear it and a situation that didn't look like it had a lot of danger suddenly became a goal against us.
"We then had to dig deep and the pleasing part for me was the reaction from everybody. It was roll the sleeves up and straight back at them and I thought we got the goal we deserved and arguably if we'd taken a couple more of our chances it was a game we could have won."