Paul Hartley's superb header gave Celtic what could prove to be a vital draw against Spartak Moscow in their Champions League qualifier first leg.
Paul Hartley headed Celtic into the lead in Moscow
Scott McDonald's cross was headed powerfully home by Hartley as Celtic took a 21st-minute lead in Moscow.
But Celtic goalkeeper Mark Brown was unable to prevent a header from the badly marked Roman Pavlyuchenko bulging the net 20 minutes later.
Brown saved well from Morais Welliton as Spartak dominated after the break.
Hartley and McDonald had been brought into the side following Saturday's win over Falkirk.
It was McDonald's first competitive start because of domestic suspension incurred while with Motherwell last season.
Hartley took the place of Aiden McGeady in midfield at the Luzhniki Stadium.
Pavlyuchenko, who broke a bone in his right hand against Krylya Sovetov at the weekend, started for the home side.
And the striker's inclusion appeared to be immediately vindicated as Celtic were put under early pressure.
Pavluchenko neatly backheeled a Welliton cross into the net from eight yards only to be ruled offside by German referee Herbert Fandel.
Stephen McManus was fortunate that Fandel ruled out another claim for a penalty after a late stamp on Vladimir Bystrov inside the box.
But Celtic began to find their feet on the tricky artificial surface and took a surprise lead after 21 minutes.
Roman Pavlyuchenko (left) put Spartak level before the break
Shunsuke Nakamura sent McDonald clear down the right and the little striker's cross found Hartley powering into the box.
And the midfielder sent his header powering into the far corner of the net from 16 yards.
Celtic looked to have subdued their opponents, but Spartak drew level after 41 minutes.
A Roman Shishkin cross found Pavluchenko rising above Scott Brown at the back post and goalkeeper Mark Brown could not get enough of his hand on the ball to prevent it deflecting into the far corner of the net.
Some hesitation in the Celtic defence almost presented Spartak with a second goal after 58 minutes, but Scott Brown cleared Titov's header across the face of goal.
Spartak squandered another chance when Welliton's cross found Pavluchenko unmarked, but the striker headed wide from 15 yards.
And goalkeeeper Brown did well to block Welliton's close-range header.
Celtic could have sneaked a win when substitute McGeady threaded a ball through to Scott Brown, but goalkeeper Stipe Pletikosa saved at the midfielder's feet as the former Hibernian man hesitated.
Spartak Moscow: Pletikosa, Shishkin, Kovac, Stranzl, Soava, Mozart, Torbinsky, Bystrov, Titov, Pavluchenko, Welliton.
Subs: Homich, Boyarintsev, Dedura, Kalinichenko, Dzjuba, Sabitov, Rebko.
Celtic: Mark Brown, Wilson, McManus, Kennedy, Naylor, Hartley, Scott Brown, Nakamura, Donati, McDonald, Vennegoor of Hesselink.
Subs: McGovern, Caldwell, Sno, Killen, McGeady, Zurawski, Pressley.
Referee: Herbert Fandel (Germany)