Celtic could only muster a draw after conceding another poor goal in the first leg of their Europa League play-off against Suduva in Lithuania.
Olivier Ntcham nodded in Mikey Johnston’s cross to give the Scottish champions a perfect start in Lithuania.
But the unmarked Ovidijus Verbickas headed home a deep free-kick and Craig Gordon twice denied the hosts a second.
James Forrest, Johnston and Moussa Dembele missed chances to take a lead back to Glasgow for next week’s return.
Celtic remain strong favourites to progress to the group stage, but picked up another injury concern when Jozo Simunovic was forced off after landing heavily on his ankle.
Defensive woes continue
Celtic started with such confidence, and had the boost of Ntcham’s early goal.
But there was more compelling evidence of the defensive vulnerability that proved so costly as they crashed out of the Champions League against AEK Athens last week.
The error-prone Simunovic, replacing the injured Jack Hendry at centre-back, again showed the carelessness which blights his game with a sloppy early pass that Suduva failed to punish.
When Vaidas Slavickas curled in a deep free-kick from just inside the Celtic half in the 13th minute, it should have carried little threat.
But Cristian Gamboa, preferred over Mikael Lustig at right-back, lost his marker and the rest of the visitors’ defence froze, goalkeeper Gordon coming off his line too late to stop Verbickas nodding in the simplest of goals.
It was a horrendous goal to concede, and a reminder of why Celtic lodged a bid for Aberdeen centre-back Scott McKenna this week, amid continued uncertainty over Dedryck Boyata’s future.
Their resources were further depleted early in the second half when Simunovic limped off, with Lustig coming into the centre of defence.
Suduva threatened only sporadically, but as Celtic stuttered, the hosts grew in confidence.
Gordon was forced to tip over a powerful drive from Rigino Cicilia before pushing a hooked effort from Julius Kasparavicius wide for a corner.
Brendan Rodgers had earlier raised a few eyebrows by giving 19-year-old Johnston just his fourth senior start, and first in Europe, ahead of the likes of Scott Sinclair and Leigh Griffiths.
But the teenager showed his quality after barely two minutes, turning his marker on the left flank before curling a right-footed cross perfectly for Ntcham to head home from close range,
Johnston might have scored himself in the 24th minute when Forrest picked him out in the six-yard box, but could only direct his header straight at Ivan Kardum.
Forrest, with a first-time drive, and Kieran Tierney, after weaving his way into the box, also brought saves from the Suduva keeper.
The impressive Callum McGregor was at the heart of much of Celtic’s best work. The Scotland midfielder weaved his way into the penalty area before Kristoffer Ajer showed good balance to beat several defenders, only to stab his final shot straight at Kardum.
Minutes later McGregor combined beautifully with Dembele, whose sumptuous dinked pass over the defence saw McGregor’s volley touched wide for a corner by Kardum.
Dembele might have scored himself in the 54th minute, but could only lash the ball into the side netting after moving menacingly onto Ntcham’s sweet pass.