The Buddies went down 3-1 to Kilmarnock at the weekend, despite dominating the first half and missing a host of chances, and now spin right into a potential banana skin against First Division Hamilton Accies in Paisley tomorrow night.
There were many aspects of the performance in Ayrshire that pleased Lennon, who conceded that had his side been more lethal in front of goal it might have been a different story.
Lewis Guy was through twice in the opening stages and couldn't score, before Killie snatched the lead against the run of play through Cillian Sheridan, while Paul Dummet had an effort booted off the line by Killie's James Fowler, who went on to score himself along with James Dayton before Paul McGowan's late consolation effort for the visitors.
Lennon said: "The good thing is we have a game very quickly to get the weekend disappoint-ment out of our system.
"Hamilton at home will be tough and we have suffered in the past against First Division sides in the cups, so the boys will be mindful of that.
"It's a massive game for us, we are at home with a place in the quarter-finals up for grabs.
"But I'd expect a reaction from this group of guys as they were very disappointed at the way things turned out at the weekend down at Kilmarnock.
"Credit to them as they had the one thing that was missing from our performance – and that was a killer touch in front of goal.
"We had some very good chances to take the lead and we were in total control of the first half. They got a goal in front and, even then, we were still on the front foot.
"Kilmarnock had an end product, and we didn't, that was the difference as we created more than enough chances to get goals."
Saints had shown a clinical side to their game in the recent home win over Hearts, and Lennon admitted that he had a feeling it may be one of those days when he saw chances being squandered.
"Last weekend against Hearts we had two opportunities and scored with them, so it can go that way sometimes," he added.
"When you play so well away from home and see so many opportunities being passed up, you do wonder if it will be one of those days and that's exactly the way it turned out.
"But I have been pleased overall with the shape of the team, the way we have been passing the ball and making things happen and we need to carry that into the Accies match now.
"As we have seen in the past, anything can happen in cup matches if you are not switched on and there have been a number of SPL teams knocked out already by SFL clubs, so we need to ensure we are not added to the list."