De Bruyne set up Romelu Lukaku, Thomas Vermaelen and Toby Alderweireld to score inside the first 32 minutes before capping a brilliant individual display by rounding off the scoring.
Belgium and City had to cope without the 28-year-old for most of last season due to two major knee injuries.
But De Bruyne has started the season like a man keen to make up for lost time.
"He has started the season in a fresh manner and you can see his exceptional quality. For me he is the best playmaker in world football," said Martinez.
"Playmakers used to stop the play to make the pass, he can execute that pass on the move. You saw him fresh, full of responsiblity and he's having a very influential role."
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De Bruyne will be a key figure for the Red Devils if Belgium are to deliver on their enormous potential by winning next year's European championships.
Victory maintained their 100 percent record in Group I of qualifying after six games.
By contrast, Scotland boss Steve Clarke admitted his side's hopes of automatic qualification are already over after a fourth defeat in six matches left them fifth in the group, behind Cyprus and Kazakhstan.
Scotland now have to rely on a playoff next March, earned via winning their Nations League group under former manager Alex McLeish.
"The group is over in terms of qualification," said Clarke with Scotland nine points behind second-placed Russia.
"We have to target third position. There are 12 points up for grabs and we have to make sure we finish third in the group.
"If we finish third in the group it means we will have performed well and give us confidence going into the playoffs in March."
Martinez showed no complacency with his team selection by naming his strongest available side with captain Eden Hazard sidelined by injury.
The gulf in class quickly told, but Clarke was bitterly disappointed with the generous defending his side could ill afford against the number-one ranked team in the world.
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Belgium's opener originated from a Scotland free-kick in a dangerous area, but in a flash Dries Mertens released De Bruyne down the left on the counter-attack and his low cross was swept home by Lukaku for his 32nd goal in his last 30 international appearances.
Clarke was handed the Scotland job in May after making his Kilmarnock side notoriously hard to beat during two seasons in charge.
That defensive resolve has so far been found wanting at the step up to international level as Belgium extended their lead thanks to slack marking at corners.
Firstly, De Bruyne's wicked low cross was turned home by Vermaelen.
And eight minutes later Alderweireld was afforded a free header from De Bruyne's delivery to head in off the underside of the bar.
"We have to improve defensively," added Clarke. "We shot ourselves in the foot.
"We spoke before the game, they are capable of scoring from open play, but from three set plays we find ourselves 3-0 down at half-time."
Belgium showed some measure of mercy on their embarrassed hosts after the break.
But De Bruyne got the goal his performance merited with a measured finished into the far corner eight minutes from time.
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