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.
"Defensively, we lacked aggression, especially in the first half". We didn't close the space quick enough.
"That will be our idea going into the game and we will look forward to working that way". We shouldn't be conceding that type of goal. Branislav is outstanding in the air.
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. We're too deep and have to press the guy who was shooting.
It was then advantage Zenit 20 minutes later when a curling shot by Kuzyayev found its way past Celtic goalkeeper Dorus de Vries putting them 2-0 up on the night. But everything was too sideways and backwards and that's about bravery and having that courage to play.
"We played a flawless game really in how the players defended and attacked".
"We should never concede that type of goal, the third goal".
Sport Express Ru have reported on the game, and they haven't been generous to Celtic with their ratings.
"If we played with a little bit more courage and belief, we could maybe have got a result", said the Ulsterman.
With a lead to protect and the clock on their side, Zenit comfortably held firm through to the final whistle to secure a place in the draw for the next round.
"We were one step away from the miracle", said Napoli s Brazilian midfielder Allan.
"We have played very well in some games and shown some great qualities".
Writing for Sport Express, Gosha Chernov suggested that the Parkhead atmosphere had played a big part in Celtic's first leg win: "Paradoxically, in St Petersburg, Celtic had twice as much of the ball as the hosts, but there was nearly no urgency". At the beginning of the first leg, I was being a realist as everyone would probably expect Zenit to go through, but what we showed in the first leg is that we're going to make it very hard for them and going to make it really competitive.