- Tag results for Romelu Lukaku
Substitute Romelu Lukaku broke the deadlock just 38 seconds after coming on midway through the second half.
Jose Mourinho's team is now six points off the Champions League qualifying places and a massive 16 behind first-place Manchester City.
Romelu Lukaku was widely criticised after United were beaten 1-0 at home by Juventus in midweek, extending his goal drought to eight games.
Belgium's second win of the fledgling tournament keeps them flying high in League A Group 2 following an opening 3-0 win in Iceland.
Wolves visit Old Trafford on Saturday, before a trip to West Ham and a home fixture against Newcastle, by which time Lukaku could be the clear leader in the race for the Golden Boot.
Eden Hazard converted a 29th-minute penalty after a foul on Lukaku, with the Manchester United striker netting a quick-fire second before adding a third in the closing stages.
Roberto Martinez's men showed their class and no hangover from their exertions in finishing third in Russia to warm-up for their Nations League opener against Iceland on Tuesday.
Romelu Lukaku opened the scoring in the 27th minute with a simple back-post header from an Alexis Sanchez cross.
United have won two of their five pre-season fixtures so far and will be keen to make a quick start in their quest to win silverware this season.
Harry Kane leads the list of goal scorers in the ongoing FIFA World Cup.
France defender Raphael Varane said he was pleased at how France’s relatively young team was maturing as they progressed.
The pace of Kylian Mbappe could cause problems in Saint Petersburg on Tuesday, but Belgium will not be short of experience at the back.
Of the 122 goals in the 48 matches so far, 31 came from players in England's top league and 29 from players in Spain.
England impressed in their opening two World Cup games beating Tunisia 2-1 in Volgograd then thrashing Panama 6-1 in Nizhny Novgorod.
Romelu Lukaku is lighting up the World Cup finals with four goals for Belgium and Didier Drogba for one could not be happier.