Celtic sit top of the Scottish top flight with 21 wins and three draws from their 24 matches, but suffered shock eliminations in the Scottish League Cup and Scottish Cup to Greenock Morton and Aberdeen respectively.
They also managed to record just three points from the UEFA Champions League group campaign and will not have the distraction of continental football in the second half of the campaign.
"The incentive now is to go unbeaten for the rest of the season," Lennon said on Thursday. "I don't know if that's been done here before at the highest level.
"We've had Champions League football, the players have entertained all season and broken records so we want to finish with a bit of style.
"We're 21 points clear after 24 games, so the improvement in our league form this season should not be overlooked."
He added; "St Johnstone have given us problems in recent years and I'm sure Sunday will be tough, but I'm looking for a reaction from the players.
"We'll come out motivated on Sunday and looking to win."
