Anthony Stokes' 87th-minute free-kick gave Celtic victory over Dundee United in their Scottish Premiership clash at Tannadice.
The game looked to be drifting towards a draw when the Irishman was brought down by United defenders Stuart Armstrong and Keith Watson at the edge of the box.
Stokes, who had set up James Forrest for the Champions League clincher in the 3-0 win against Shakhter Karagandy at Parkhead on Wednesday night, picked himself up and curled the free-kick over the wall and past Radoslaw Cierzniak, with the ball going in off the post.
The only downside was the injury to Sweden defender Mikael Lustig, who was carried off on a stretcher early in the second half after appearing to fall awkwardly following a hefty challenge by United defender Gavin Gunning.
As a reaction to their Champions League efforts in midweek, it was a good day's work by the visitors.
Celtic were rewarded for getting into the group stages by being pitched into a group with Barcelona, AC Milan and Ajax.
To that end, Lennon strengthened his squad further.
Israel international midfielder Nir Biton's move to Celtic from FC Ashdod was confirmed on Friday while Finnish striker Teemu Pukki checked in this morning at Celtic Park from Schalke 04.
Neither was involved against United but following their energy-sapping win over the Kazakhstan champions, Lennon made three changes to his starting eleven,
Defenders Virgil van Dijk and Emilio Izaguirre and striker Derk Boerrigter came in for Charlie Mulgrew, James Forrest and Georgios Samaras.
United boss Jackie McNamara made five changes to the side which beat Dumbarton 3-2 in the League Cup in midweek with Gunning, Watson, Armstrong, Gary Mackay-Steven and Nadir Ciftci starting, and John Souttar, Calum Butcher, Ryan Gauld, Mark Wilson and Brian Graham all dropping to the bench.
Celtic started with some purpose, carving out a chance in the second minute through Kris Commons.
The Hoops midfielder picked out the advancing Lustig with a perfectly-weighted pass but the defender's shot, after a second of hesitation, was blocked by Watson with the home side gratefully clearing their lines.
Moments later, Van Dijk slipped all too easily through the United defence and should have scored but instead lifted the ball over the bar from eight yards out.
It was further evidence that the champions were comfortably in control.
In the 17th minute Boerrigter's cross on the run from the left was only cleared to Stokes at the edge of the box and his volley whistled inches past Cierzniak's left-hand post.
A minute later Van Dijk moved up to bolster the attack again and sent a powerful drive from 25 yards just wide of the target.
United had their first real chance in the 23rd minute when Armstrong planted a cross from the left on to the head of the unmarked David Goodwillie but his weak header from 10 yards was easily saved by Hoops keeper Fraser Forster.
Five minutes later Celtic skipper Scott Brown hauled down Mackay-Steven 25 yards from goal and from the resultant free-kick by Ciftci, a curled shot heading in at the post, Forster made a good save by diving to his right to punch away.
The start of the second half was tepid but in the 55th minute Lustig signalled furiously after landing beside Gunning and the game stopped as he was strapped up and taken off, to be replaced by striker Amido Balde with Adam Matthews moving to right-back.
The United defender required treatment before he came back on but the tempo dipped.
In the 73rd minute a fine cross by United left-back Andrew Robertson just evaded the sliding Armstrong at the back post having bypassed Forster but that aside, the first goal of the game looked far from inevitable.
Balde might have scored from Commons' flighted corner with eight minutes remaining but he headed wide of the target from six yards out, before the former Nottingham Forest player drilled wide of the target from just inside the box.
But with three minutes to go Stokes took the points back to Glasgow with a free-kick, which must have sickened the home side.