The Briton had qualified sixth but only had to prevent teammate Valtteri Bottas from outscoring him by eight points to seal the deal with three rounds to spare.
In the end his finishing position mattered naught, with Bottas spinning out of the points at the very first corner in soaking wet conditions as he attempted to avoid friendly fire between the Renault drivers.
His victory was made all the more remarkable for his early race difficulties as his Mercedes struggled to adapt to the combination of a greasy new track surface, standing water and cool ambient temperatures.
With a third of the 58-lap race gone he languished in sixth and almost 25 seconds off the lead.
But the race came towards him the longer it went on. His superb judgement in tricky conditions came to the fore as his chief rivals spun off the track, and his beautiful touch for the tyres enabled him to make one fewer stop than all but one finisher, rocketing him up the order.
He ended the race with no tread left on his tyres, but by the time the chequered flag dropped it didn’t matter - the Briton had built an imperious 31-second lead testament to his masterclass drive and befitting a seventh world championship.
“I’m definitely a bit lost for words,” an emotional Hamilton said post-race. “I wouldn’t be able to do this if I didn’t join this team. The journey we’ve been on is monumental.
“A big thank you… to my family. We dreamt of this when I was young, when we were watching the grands prix, and this is way, way beyond out dreams.”
The first among those left in Hamilton’s irresistible wake was Sergio Perez, who likewise stopped only once to lock in track position.
But the Racing Point lacked the pure pace of the Mercedes car and so had to defend heavily on badly worn tyres against Ferrari drivers Charles Leclerc and Sebastian Vettel late in the race to secure his first podium in two years and highest finish since his sophomore season in 2012.
“One more lap on those tires and I think they would have exploded!” he said. “I think the team did a fantastic job in terms of strategy.
“Lewis today was extremely strong… but we managed to get a good result.”
The battle for third came down to the final lap, with Leclerc leading Vettel in an assault of Perez’s second place.
But the Monegasque misjudged his braking into turn 12 and ran wide in a botched pass, allowing Vettel to slip past to pinch his first podium finish of the year.
“It was a very intense last lap,” Vettel said. “A bit of a surprise to snatch the podium.”
Leclerc was shattered to drop off the podium, having impressively risen from 14th at the end of the first lap by perfectly timing his tyre changes, at both pit windows making himself the first driver to stop.
He was lucky to lose only one place through the error, finishing just half a second ahead of McLaren’s Carlos Sainz, who had started a similarly lowly 15th after a penalty for blocking during qualifying.
Red Bull Racing teammates Max Verstappen and Alex Albon followed disappointedly in sixth and seventh. Both were in contention for victory in the first half of the race before succumbing to spins, Verstappen while trying to pass Perez and Albon on severely old tyres.
Lando Norris snatched eighth place two laps from the finish from polesitter Lance Stroll, who plummeted from a comfortable race lead to a dejected ninth place after his second pit stop when he was unable to get heat into his fresh tyres.
Daniel Ricciardo completed the points-getters in 10th for Renault.