Brendan Rodgers rues lack of bravery as Bhoys are taught a lesson
Zenit 3 Celtic 0
Celtic crashed out of the Europa League in calamitous style with a 3-0 defeat by Zenit St Petersburg in Russia.
The Bhoys' deserved 1-0 lead from the first leg of the last-32 clash at Parkhead last week was wiped out before half an hour had been played, with Brendan Rodgers' side culpable.
Returning defender Branislav Ivanovic, celebrating his 34th birthday, put Zenit in front with a header from a poorly-defended corner in the eighth minute before attacker Daler Kuzyaev fired in a long-range drive in the 27th minute which had Parkhead keeper Dorus de Vries grasping air.
Still, a goal was all Celtic needed to go through to the last-16 but in the 61st minute striker Aleksandr Kokorin, who had previously scored against the Hoops for Dinamo Moscow, made it 3-0 on the night and 3-1 on aggregate.
Disappointed Ulsterman Rodgers lamented: "Defensively we lacked aggression, especially in the first half. We didn't defend forward well enough. But, at 2-0 down, we were still in the game and we had to show bravery.
"Second half, we started okay, but we again conceded possession too cheaply.
"Across two games, we were much better than them in the first game. In this one, if we had showed more courage and more belief, we could have got a result.
"I think there's still an awful lot of work for us to do, but there have been a lot of positives."
An expensively-assembled Zenit side had looked rusty in Glasgow in their first competitive game in two months due to Russia's winter break.
However, despite looking no better than decent they were fit enough and good enough to recover the tie, although they were given some help by the visitors.
The stadium's roof was closed over, which was good news for the players and 50,492 supporters, including several hundred in green and white, in light of the sub-zero temperatures outside.
Celtic were unchanged from the first leg while Zenit brought back former Chelsea defender Ivanovic and midfielder Matias Kranevitter.
The Scottish champions looked at ease from kick-off in a subdued atmosphere only to be stunned by the early goal.
De Vries made a decent save, turning a long-distance drive from Leandro Paredes past the post for a corner, but when the Argentinian delivered his set-piece into the box, Ivanovic rose to bullet in his header with centre-backs Jozo Simunovic and Kristoffer Ajer unable to get in a real challenge.
Moments later, Kokorin drove a weak shot at De Vries when he could have taken the ball in closer, before Paredes fired a 30-yard free-kick just over the bar.
Zenit's second goal also appeared avoidable as Kuzyaev, after taking an Anton Zabolotny pass, fired high past De Vries from 25 yards with the Dutchman appearing to misjudge the flight of the ball.
Tom Rogic replaced Eboue Kouassi for the start of the second half, the Australian midfielder sending a shot over the bar within a minute of the restart.
However, there was more woe for the Hoops when, with the Parkhead defence in disarray again, Kokorin got in front of right-back Mikael Lustig and bundled in No.3 from a few yards out, Ivanovic supplying the cross.
Celtic tried to fight back but they looked all out of hope.
Zenit keeper Andrei Lunev saved an Olivier Ntcham shot and there was plenty of Celtic hustle and bustle in the final stages but there was no way back from a night in Russia which ended with plenty of regret.
ZENIT WIN 3-1 ON AGGREGATE
ZENIT: Lunev, Ivanovic (Smolnikov 87), Mevlja, Mammana, Criscito, Kranevitter, Paredes, Kuzyaev, Rigoni (Driussi 84), Kokorin, Zabolotny (Erokhin 76). Subs not used: Lodygin, Terentjev, Poloz, Zhirkov.
CELTIC: De Vries, Forrest (Musonda 71), Lustig, Simunovic, Ajer, Tierney, Kouassi (Rogic 45), McGregor (Sinclair 62), Brown, Ntcham, Dembele. Subs not used: Hendry, Edouard, Bain, Miller.
Match rating: 6/10
Referee: Antonio Lahoz (Spain)