Celtic's narrow 2-1 defeat at Camp Nou last week is still fresh in the mind but the Northern Irishman wants all the attention to be on the SPL and the game against United, before the visit of Barcelona next Wednesday.
After watching his side book a place in the Scottish Communities League Cup semi-finals with a 5-0 home thumping of St Johnstone, Lennon said: "We have three or four days before we play Dundee United and that is our main focus."
Lennon added: "Barcelona is coming up next week but I don't want to talk about that until after Dundee United on Sunday.
"Before last night's game I said to the players that last week they were well motivated, in a nice climate, going out at the Nou Camp.
"It was different (against St Johnstone), maybe 15,000 to 20,000 people there, but I said their attitude had to be the same and I got that."
Indeed, Lennon witnessed his side return to top form against a Saints side whose eight-game unbeaten run come to an abrupt end.
Hoops midfielder Kris Commons was credited with a hat-trick although his first goal came when his shot took a deflection off St Johnstone midfielder Liam Craig. Further goals from Gary Hooper and Charlie Mulgrew gave a true reflection of the gulf between the sides on the night.
He said: "It was a dominant performance and one that I wanted. The ones who played on Saturday knew that had fallen below the standards they set themselves.
"We have moved on from the weekend but I will be demanding more as the season goes on."