United is off to Benfica next, an Oct. 18 date, while CSKA hosts Basel.
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Any drama in this one was sorted quickly, as United did not have the Moscovian trouble of its rivals Liverpool.
Martial crossed from the left for Lukaku to head home in the fourth minute, and Henrikh Mkhitaryan earned a clear-cut penalty to give Martial his goal in the 19th.
The French youngster added his second assist on as easy a goal as Lukaku will score, and United led 3-0 at the break.
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Mkhitaryan scored a goal in the 57th minute, right when it looked like Martial was set for his brace. Igor Akinfeev pushed a shot into the path of United’s Armenian playmaker for a left-footed finish.