Zlatan Ibrahimovic's sixth goal of the season was the difference as Manchester United laboured to 1-0 victory over Zorya Luhansk in Thursday's Europa League tie at Old Trafford.
It took United 69 minutes to register an attempt on target but when it came it proved decisive as Ibrahimovic headed substitute Wayne Rooney's scuffed shot home from close range.
Ukrainian outfit Zorya failed to live up to their minnow status, producing a gutsy display, although that was due mainly to United's lethargic approach.
However, it was a night of positives for Jose Mourinho as United moved to within a point of Group A leaders Fenerbahce with their first Europa League victory of the season.
For the second game running there was no Rooney in the United starting XI as Mourinho fielded a strong side featuring Ibrahimovic, Marcus Rashford and Paul Pogba.
Yet despite their star-studded line-up, United struggled to scale the heights seen against Leicester in what turned out to be a frustrating first half for the hosts.
The bright Ivan Petryak spurned the first clear opening, steering Zeljko Ljubenovic's cut-back over the bar on five minutes as Zorya gave as good as they got in the opening stages.
It took United 19 minutes to fashion a chance of their own as Ibrahimovic's deflected 25-yard strike looped agonisingly wide of the target.
The hosts went even closer a minute late when Rashford came within a ball's width of scoring as his thunderous half-volley cannoned off the underside of the ball and down onto the wrong side of the goal-line.
United finished the half strongly as Juan Mata headed Pogba's wicked cross over the bar before Jesse Lingard saw a goal-bound header turned away by the resilient Zorya defence.
From the resulting corner, Marouane Fellaini steered a header onto the roof of the goal but there was to be no breakthrough as United entered the break level.
United were almost punished for a sloppy start to the second period, but Ljubenovic was unable to get a toe on Olexandr Karavayev's enticing cross on 50 minutes.
As United toiled for the opener, the first shot on target fell to the visitors as substitute Paulinho drew Sergio Romero into action on 67 minutes.
Mourinho responded immediately by bringing on Rooney and it had the desired effect as he had a hand in United's opener.
Timothy Fosu-Mensah picked out the United captain in space in the area and his mis-hit effort fell perfectly for Ibrahimovic to convert from two yards out.
And there was no way back for Zorya as fatigue set in, allowing United to end September - which began with three straight defeats - with a third-successive victory.