An injury-time goal at the end of the first half earned Lokomotiv Moscow a share of the points and the Dons now face the tough task of trying to take something from their next tie away at Atletico Madrid.
The match got underway in wintry conditions with the wind and snow causing problems for both teams. Lokomotiv appeared to settle quicker and Dons goalie Jamie Langfield was called into action to make a fine stop after ten minutes.
Dmitry Sychev let fly with an angled drive from the edge of the area and Langfield did well to push the ball away before Barry Nicholson cleared the danger.
Lee Miller passed up a gilt-edged opportunity to fire the Dons in front midway through the first half, blazing just wide of target with the goal at his mercy.
Dons skipper Scott Severin picked out Sone Aluko on the left flank with a raking 50-yard ball from the back and the loan signing saw his cross palmed into Miller's path by Lokomotiv goalie Ivan Pelizzoli. Miller opted for power rather than placement and his effort flew just wide of target.
At the other end, Langfield was called into action once more to push a Peter Odemwingie free-kick over the bar. Then from the corner kick, Aberdeen had Chris Clark to thank for clearing a Sychev header off the line.
The Dons rode their luck and the bumper Pittodrie crowd were celebrating minutes later as Zander Diamond rose above the Lokomotiv defence to head home from a Nicholson corner.
With half-time approaching, Lokomotiv were denied an equaliser by the woodwork when Sychev struck the post.
But the visitors eventually levelled in injury time at the end of the first period when Branislav Ivanovic rose above Andrew Considine to head home from Alexander Samedov's corner kick.
Goalscoring chances were at a premium after the break and the visitors appeared content to settle for a valuable away point.
Aberdeen failed to threaten the Lokomotiv goal in the second half and Jimmy Calderwood's men now face an uphill task to make further progress.