Saints prevailed on penalties against Aberdeen on Tuesday to book a place in the last four of the Scottish League Cup. But Lennon was quickly looking ahead to Saturday's SPL clash against Hibernian at Easter Road. Lennon said:
"In many ways we have progressed in the last 18 months in terms of our style and our league position last season.
"We managed to get through to a semi-final at the fourth attempt from a quarter-final so in many ways we have progressed, but in other ways we haven't.
"We are coming into this match on Saturday on the back of a monumental result and performance at Aberdeen so confidence will be high, but we must guard against complacency.
"In recent times, when we get a great result we have taken our foot off the gas in the next game and failed to apply ourselves fully.
"That's the mentality we must change, starting with the game on Saturday. No excuses, we must bring our best in every game."
Saints have dropped to second bottom after three consecutive SPL defeats, but they are only six points behind second-placed Hibs.
"We have shown in flashes what we are capable of this season and we must now show consistency," Lennon said.
"We have seen St Johnstone string together five results on the trot, Inverness winning three, Aberdeen were undefeated in 13 games until the other night.
"We need to make sure it's our turn to put on a run, and it's about mental strength, character and playing for each other."