Endurance was the quality that Celtic had to cherish. A sense of anxiety needed to be overcome before they were able to celebrate reaching the knockout stages of the Champions League. Even on a night of great tension in Glasgow, minds wandered from the play here. The home side had to better Benfica's scoreline at the Nou Camp to progress, but that game finished 0-0 only seconds before full-time at Celtic Park, and anxiety was rife.
"Horrible," was the way Neil Lennon, the Celtic manager, described the closing minutes of time added on, but that emotion was a measure of what was at stake. He can now contemplate the opponents that the draw on 20 December might bring, including Manchester United, but there was time to dwell on the way that Celtic went from being dismissed as outsiders in the competition to deserving their place in the last 16.
"It means the world to me," Lennon said. "I'm a young manager and it's my first year in the Champions League. We performed a miracle, because nobody gave us a prayer coming into this group. People laughed when I said the aim was to qualify, but we have a decent team, with young, hungry players. We want to keep progressing."
Celtic's last Champions League tie in Glasgow was a 2-1 victory over Barcelona last month and the emotion, the sheer intensity of feeling of that night was a backdrop to this game. Lennon did not want his players to be remembered for beating the Spanish side only to then fail to progress from Group G.
Spartak were obliging visitors, since they arrived in a state of unrest. Their coach, Unai Emery, was sacked following a 5-1 defeat to local rivals Dynamo, and Valery Karpin, a former Spartak manager, was in charge again as a caretaker. They began the game in a sprightly mood. When Kim Källström, the Spartak midfielder, was unchallenged as he played a one-two with Artem Dzyuba before steering a left-foot shot just wide, there was cause for Lennon to be irked, and to rail at his players.
The intention must have been to place unbearable pressure on Spartak. Celtic knew the visitors' defence was vulnerable and there must have been a sense of familiarity when Juan Insaurralde failed to cut out Georgios Samaras's cross-field pass. Insaurralde's error allowed the ball to bounce to Hooper and he lashed it past the goalkeeper Sergei Pesyakov from 20 yards out.
Celtic found their assertiveness, and the crowd was roused, but aberrations were possible in both defences. When Efe Ambrose let himself to be barged aside by Emmanuel Emenike, the Spartak forward surged upfield before passing to Ari, who chipped a shot over Fraser Forster and into the net in the 39th minute. Only the half-time interval prevented a sense of unease becoming established.
The occasion called for boldness and the mood was spirited, although the delicate balance of the circumstances could also prompt uncertainty. Moments after Samaras hit the post, a cheer spread round Celtic Park and the home fans began to sing of "Going to Wembley", where the Champions League final will be played. The rumour was of a goal for Barcelona, but the game at the Nou Camp was still 0-0.
Celtic had to retain their purpose and it only needed a moment of assertiveness to re-establish the lead, though, and a misjudgement came to Celtic's aid, with Marek Suchy acting rashly as he pushed Samaras over inside the penalty area. Kris Commons was emphatic in the way he lashed the spot kick high into the net. "I didn't watch," Lennon grinned. "I saw our last couple of penalties and we missed them, so I turned my back and waited for the roar."
When Källström was sent off after receiving his second yellow card for a foul on Commons, who was carried off, apprehension was still evident because there was five minutes of time added on to play. "We saw the game out pretty well," Lennon said. "I was trying to stay calm, but inside my stomach was churning."
Celtic's progress into the last 16 was the reward for a team that is growing into its potential. "It's a great night," Lennon added, as if still trying to savour it all.
Man of the match Commons.
Match rating 7/10.
Referee F Brych (Ger).