Adnan Januzaj made his international debut for World Cup dark horses Belgium, as Romelu Lukaku hit a hat-trick in their 5-1 friendly win over Luxembourg.
The Chelsea striker gave Belgium the lead at Genk's Cristal Arena and restored their advantage following Aurelier Joachi's equaliser.
Lukaku completed his treble in the 54th minute before Nacer Chadli and a Kevin de Bruyne penalty extended the Red Devils' margin of victory.
Januzaj scored four goals for Manchester United last season
Januzaj made his bow as a second-half substitute having declared his international allegiance just a month ago.
"He gives us an extra dimension," said Belgium coach Marc Wilmots, who warned the 19-year-old "faces a lot of competition" if he is to establish himself as a regular.