The Manchester City winger started for the Red Devils who won with a first-half goal from Youri Tielemans and injury time strike from Romelu Lukaku.
Doku faced his Club team-mates Josko Gvardiol and Mateo Kovacic who both started for Croatia.
He had an early shot on target that was saved by Dominik Livakovic and had a brilliant run from his own half to set up former City great Kevin De Bruyne who fired just wide.
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Gvardiol, played just short of an hour, as he continues his step up from the fractured leg which ruled him out for much of the season at the Etihad Stadium.
Kovacic was also replaced after 59 minutes while Dok was replaced with 17 minutes remaining.
Belgium have a friendly against Tunisia in Brussels on Saturday before they travel to North America with their opening game against Omar Marmoush’s Egypt on 15 June.
Croatia have another home friendly against Slovenia on Sunday before their World Cup Group L opener against England on 17 June.
Earlier in the day, Abdukodir Khusanov played the whole game as his side fell to a 2-0 friendly defeat against Canada.
After a promising opening 45 minutes for the 22-year-old’s side, Uzbekistan had the most clear cut chances in front of goal, but were unable to carve out any scoring opportunities.
It took just 13 minutes into the second half until the deadlock was broken as Jonathan Osorio opened the scoring for Canada at the 58-minute mark.
Jayden Nelson later added an insurance goal one minute into stoppage time as Jesse Marsch’s side claimed a 2-0 win at the Commonwealth Stadium.
Uzbekistan’s focus now moves to New York to play their final pre-tournament game, against the Netherlands on Monday 8 June.
For the World Cup beginning on 12 June, Uzbekistan are slotted into Group K alongside Portugal, DR Congo and Colombia.
