Georgios Samaras' last-gasp header gave Celtic a dramatic 3-2 Champions League Group G victory over 10-man Spartak Moscow in the Luzhniki Stadium.
Celtic striker Gary Hooper gave visitors the lead in the 12th minute before Emmanuel Emenike netted twice for the Russian club, once either side of the break.
Celtic levelled in the 72nd minute after a drive from substitute James Forrest, who had replaced Victor Wanyama, deflected in off Spartak captain Dmitri Kombarov and to cap a remarkable night for the visitors Samaras headed in an Emilio Izaguirre cross seconds after the regulation 90 minutes.
Spartak had lost the services of keeper Andriy Dykan to injury, his place taken by Sergei Pesyakov. The number two keeper, though, had little chance with Hooper's well-taken goal, which stemmed from Kallstrom's reticence in a 50-50 tackle with Wanyama.
The powerful Hoops midfielder played the ball wide to right-back Mikael Lustig to deliver low for the former Scunthorpe striker to clip the ball in from around six yards.
It looked like Lennon's side would take a lead into the interval but four minutes from the break Emenike knocked the ball past Forster from close range after being set up by Ari, who had latched on to a delightful long ball by Kallstrom.
Emenike grabbed his second goal three minutes into the second period. Forster looked slow going down to deal with Ari's drive from long distance and when he spilled it, Demy de Zeeuw pounced to play the ball across goal for the Nigeria striker to tap in.
There was some needless controversy surrounding Insaurralde's dismissal. The Spartak defender hauled Hooper back as he raced through on goal from Mulgrew's pass but at first French referee Tony Chapron played on, then, after presumably taking some instruction from one of his officials, he showed the Argentinian the red card.
Mulgrew's free-kick, when it was eventually taken, was punched away by Pesyakov, who dealt comfortably with Emilio Izaguirre's volley from the rebound. But there was more drama to come in the 72nd minute when Forrest's angled shot from 12 yards, after good work from Samaras and Hooper, was saved by Pesyakov before going in off Kombarov.
Pesyakov made a good fingertip save from Joe Ledley, who had replaced Mulgrew, and the keeper saved again from Hooper. But with the game in added time Samaras rose to head Izaguirre's cross into the far corner of the net.