The 25-year-old striker has established a reputation as one of world football’s most fearsome frontmen over recent years, with a forgettable spell at Chelsea put firmly behind him.
Goal-laden stints at West Brom and Everton earned Lukaku a £75 million ($101m) move to Old Trafford in the summer of 2017, and he has repaid that show of faith with 27 goals across all competitions.
He has also become an important figure in a golden generation of Belgian talent, although his fellow countrymen can be quick to pull him up on the faults which still exist in his game.
“People are laughing at his control but he's a boy who after training takes 20 balls and continues to train. I respect him a lot for that.”
Mertens is set to be another key man for Belgium this summer at World Cup 2018, with the 31-year-old having followed up a 34-goal haul last season with another 22 efforts for Serie A title challengers Napoli this term.
He is set to be joined in the fold by several other creative talents, such as Manchester City star Kevin De Bruyne and Tottenham playmaker Mousa Dembele.
Eden Hazard will also be expected to provide inspiration on Russian soil, but Mertens insists that the Chelsea talisman is not the most technical player within Roberto Martinez’s ranks.
He added when quizzed on that subject: “Everyone is going to think about Eden Hazard.
“But I'm going to say Jan Vertonghen. He is very technical for someone tall [and playing in a] defensive position.”
Mertens & Co. are set to open their World Cup campaign against Panama on June 18, before going on to face Tunisia and England in their other Group G fixtures.
Before that, though, Lukaku still has one more domestic outing to take in, with Manchester United hoping to see him shake off an ankle problem in time to grace an FA Cup final clash with Chelsea on Saturday.