The Hoops boss is currently serving a three-game touchline ban - with another three-game ban suspended - for running on to the pitch at the end of the Scottish Cup semi-final against Hearts at Hampden last month to confront referee Euan Norris, who had awarded the Tynecastle side a controversial penalty which saw Celtic dumped out of the cup.
With Celtic trailing 1-0 to United on Sunday, the Hoops' claims for a spot-kick when Emilio Izaguirre's cross hit the hand of Keith Watson were ignored, and Lennon said: "What is the difference between the penalty given against us in the semi-final and that handball?... You've got to be consistent."
Lennon continued: He (ref Iain Brines) will just say it wasn't a penalty but I want to know what is the difference.
"I am going to get accused of being a sore loser or blaming referees but it's not the point, what I want is an answer and I don't feel I get them."
It wasn't just the ref who endured the wrath of the Northern Irishman, who threatened to extend the season for some of his players beyond next week's final game against Hearts because of their performances.
"It was a disappointing result and I am annoyed," he said. I was not happy with the attitude of some of the players out there today. Some of them are on holiday mode already. We need to knuckle down again this week. We are making some plans with fitness testing this week to compare to where they are when they come back for pre-season.
"So they were in for a tough week but it may even be tougher now after today because I am not happy with a few of them. They better be (ready for one final push) otherwise they won't be going on holiday just yet."
United boss Peter Houston said he was "embarrassed" at his side's 5-0 defeat at Rangers in midweek, but was happy with the way they responded against the other half of the Old Firm.
"I was proud of them this time," he said. "I was hoping for a reaction and I got a reaction."
Source: PA
Source: PA