The Paisley side failed to win any of their first seven Scottish Premiership fixtures of the season as Lennon found his position under threat.
But a 2-0 win over Hearts at Tynecastle bought him some breathing space as his side embarked on a run of nine games that included just one defeat - a 4-0 thrashing by Dundee United at the end of October.
However, back-to-back beatings by Aberdeen and Motherwell have brought them back to earth with a bang and they now face a rampant United for a second time on Boxing Day, with Lennon fearing a two-game blip could soon become another season-wrecking run.
Lennon said: "We've had a taste of what a poor run is like and we know how quickly the situation can evolve. We want to get back to winning ways as soon as we can and pick that momentum back up.
"I look at United and they are scoring goals and playing with confidence. That's what winning games does for you. Losing games brings out a different side.
"We've been there as a group and I've told the players that we are not going back there. It's about making sure you take a professional pride in what you do."
While the Buddies were a sorry state as they went down 3-0 to Motherwell at Fir Park, Thursday's opponents notched up their sixth win on the bounce.
There was some comfort for Lennon, however, as Jackie McNamara's Tannadice side won only 1-0 against Ross County having scored at least four goals in their five wins beforehand.
The Saints boss has promised not to change his side's style of play for the Terrors' visit but he has demanded they get back to basics.
"We know just how well Dundee United are playing," said Lennon as he praised the likes of Ryan Gauld, Stuart Armstrong and Andrew Robertson. "It's six straight wins and 22 goals scored in the process. Absolutely incredible. It will be a stern challenge for us defensively.
"We have to respect what they are doing, with the dynamics and movement of their play. From middle to front they are dangerous and their full-backs love to go forward too.
"They have high energy and Jackie deserves a great deal of credit for inheriting these players and turning them into high-impact SPFL players.
"But like any opposition we look at where their strengths are. But you can also find weaknesses and it's about trying to counteract their good points and exploit the others. What is important for my team is that we play to our strengths.
"The last time we played United, there was no doubt that was our worst performance of the season. There was glimpses of that on Saturday against Motherwell. We need to get back to doing ordinary things extraordinarily well.
"When we go out and stick to a game plan, we are a good team. But when we abandon those principles we are a bad team."