The Buddies' 3-0 defeat by champions-elect Celtic at Parkhead on Saturday was comprehensive but the collateral damage could have been worse.
With all their bottom-half rivals losing, the Paisley side remain in 11th spot but only three points behind eighth-placed Kilmarnock who have played a game more.
Ahead of the visit of St Johnstone on Tuesday night, Lennon looked for a big effort from his players in the remaining fixtures.
"They are all big games," he said. "The margin for error is slim so you have to be at your best.
"Now is the time for big hearts and big performances.
"We can't afford to let opportunities pass us by, we have to give everything for the cause and we can't have any regrets when we come off the pitch."
The St Mirren boss, however, concedes that there is no great secret to escaping trouble.
He said: "It is about winning. Scoring goals and keeping the back door shut. It is as simple as that.
"The key message is to get that extra one or two per cent in application
"We took positives from the Celtic game, especially with our first-half performance where I thought we were unlucky to come in a goal down at the interval, although Celtic deserved to win.
"We have to continue that hard work in the games ahead."
Lennon said: "I would like to pass on my congratulations to Tommy Wright and his staff at St Johnstone for securing a top-six spot. It is a great achievement.
"And I would like to wish Tommy all the best following his surgery.
"They have had mixed fortunes of late but they have a good balance to their team."
St Johnstone assistant manager Callum Davidson is sure his players have the commitment and motivation to maintain their intensity after qualifying for the Scottish Premiership top six.
Saints clinched the final top-half place with a 2-0 win over Hibernian on Saturday but they are seven points off fifth-placed Inverness and a further two behind Dundee United.
However, Saints now play three teams below them in the league ahead of the split.
The Perth side pipped Inverness to a Europa League place last season after taking 10 points from their final five matches and fourth place could be enough for a European spot this term.
And they have the added incentive of staying on form ahead of their William Hill Scottish Cup semi-final against Aberdeen on April 13.
Davidson, who will again deputise for manager Wright in Paisley, said: "With the semi-final coming up, you need to win the games going into it. You don't want to go into it on a couple of poor performances.
"It's key that you stay at that level of intensity right to the end of the season. Two years ago we didn't win a game in the top six and last year we won three games. So I think we have learned from experience and understand these games are just as important."
The former Scotland left-back added: "We have three games now against teams below us but these guys are fighting for their lives. I have watched St Mirren and they play some really good football and they have been pretty unlucky not to get the results their performances have shown.
"So it's going to be a really tough game. But we are going there wanting to win the game because we want to put pressure on Inverness. If we can get as close to them before the split, then it gives us a great chance."
Davidson was in charge on Saturday as Wright recovered from surgery in hospital, although the Northern Irishman is regularly in contact.
"It was certainly different," Davidson said. "Normally my work is done when it comes to Saturday morning and Tommy does all the work on Saturday.
"It was slightly different but it made it easier that we won.
"Tommy is always in contact. We have the same discussions as if he was in, about team selection and who is training well.
"He will pick the team for Tuesday night after we discuss how training went."
- Sports & Recreation
- St Johnstone
- Tommy Wright
- Callum Davidson