Manchester United were held to a 1-1 draw by Rostov in the first leg of their Europa League last-16 clash on Thursday, leaving the tie in the balance ahead of next week's return fixture at Old Trafford.
The fit-again Henrikh Mkhitaryan scored the opening goal with United's first real chance 10 minutes before half-time, the Armenian finishing off a cute cutback from Zlatan Ibrahimovic.
Mkhitaryan's return was a timely boost for United, having not featured since the win over Saint-Etienne in the last round due to a hamstring problem, but his side could not hold on to their lead.
Aleksandr Bukharov equalised for Rostov eight minutes into the second half, getting between Chris Smalling and Phil Jones to take Timofei Kalachev's lofted pass on his chest and finish well.
Rostov could even have snatched a comeback victory in their first ever meeting with English opposition, but Aleksandr Erokhin's strike curled away from goal.
Jose Mourinho experimented with a back three ahead of Monday's FA Cup quarter-final tie at Premier League leaders Chelsea, but United were unable to record a fifth consecutive Europa League clean sheet and will have work to do in next week's second leg.
Christian Noboa had the first strike at goal in the second minute but Sergio Romero made a comfortable save, before Paul Pogba miscued a shot when found by Ashley Young in the Rostov box in a rapid start to the game.
Mourinho complained about the poor state of the Rostov pitch before the match and it started cutting up almost immediately, affecting the passing rhythm of both sides, while Rostov were also disrupted by having to replace the injured Vladimir Granat after 18 minutes.
United gradually took control of a poor-quality encounter and the visitors opened the scoring after 35 minutes with their first shot on target, through the returning Mkhitaryan.
Marouane Fellaini took a long ball down on his chest and slipped a pass behind the Rostov defence for Ibrahimovic, who used the outside of his right boot to neatly pick out Mkhitaryan for an easy close-range finish.
Ibrahimovic, who will miss United's next three domestic games through suspension after elbowing Bournemouth's Tyrone Mings, flashed a drive over the bar soon after the restart.
And Rostov then drew level after 53 minutes with a goal created out of absolutely nothing.
Kalachev was given space to drive into United territory and he floated a delightful pass into the box for Bukharov to chest down and blast a fine finish past the helpless Romero.
443 - Man Utd have conceded their first goal after 443 minutes without conceding in the Europa League. Shock. — OptaJoe (@OptaJoe) March 9, 2017
Rostov went close to taking a shock first-leg lead when Erokhin's shot swerved wide after he was set up by Dmitri Poloz, while Kalachev slashed an effort off target from just outside the area, as United toiled on the difficult surface.
Home captain Aleksandr Gatskan almost won the game with three minutes remaining, but Romero saved his powerful volley, leaving the tie finely poised.