Ivan Schranz’s neat finish in the seventh minute was the difference as the Red Devils - denied two goals by VAR - went down at the Frankfurt Arena.
Belgium now have work to do as Domenico Tedesco’s side find themselves third in Group E ahead of Ukraine, who were humbled 3-0 by leaders Romania earlier in the day at Munich Football Arena courtesy of goals from Nicolae Stanciu, Razvan Marin and Denis Dragus.
Belgium, ranked third by FIFA, had a host of chances throughout the 90 minutes but couldn’t find the necessary breakthrough.
Doku showed his pace and grace down the right on three minutes, playing in De Bruyne centrally who passed pinpoint to Romelu Lukaku but the Chelsea forward couldn’t finish when well-placed.
De Bruyne harried goalkeeper Martin Dubravka on 21 minutes, leading to a careless clearance from the Newcastle stopper to Leandro Trossard but the Arsenal playmaker blasted high and handsome.
Meanwhile, Everton’s Amadou Onana met De Bruyne’s 37th minute corner from the right, but he could only head straight at Dubravka.
Despite these chances, it took a fine save from Belgium’s Koen Casteels to avoid a 2-0 scoreline at the break, diving to his left to get a strong hand on Lukas Haraslin’s volley from inside the penalty area.
Belgium came out strong for the second half and thought they were level just before the hour mark with Lukaku wheeling away in celebration after meeting Onana’s header. VAR intervened and the goal was disallowed for offside against the giant No.10.
The impact of KDB and Doku was there for all to see as Belgium turned up the heat on Slovakia in search of an equaliser.
De Bruyne found Lukaku on 62 minutes but the former West Brom, Everton, Manchester United and Inter Milan striker couldn’t finish with his weaker right foot.
Then, moments later, Doku – a pest down the left against Francesco Calzona’s men – crossed into the box. Dubravka could only parry to Johan Bakayoko but the PSV forward’s shot was cleared off the line.
Doku was replaced by Lois Openda on 84 minutes and he cut back for Lukaku to hammer home two minutes later – but, for the second time in the afternoon, VAR came to the fore to cancel the goal out for a marginal handball by the RB Leipzig winger in the build-up.
Belgium keep pushing and pushing but couldn’t find the leveller as the clock ticked down to full-time.
Belgium’s next assignment sees them take on Romania on Saturday, kick-off 20:00 (UK) in Cologne’s RheinEnergieStadion.
