Though Tottenham eventually grew into the match, given the first 33 minutes as evidence, the Belgian's presence in midfield could prove crucial this season.
It certainly did in the second half, where it took Dembele just over 20 minutes to open his account in another pocket of London. A tremendous individual effort in the 67th minute sent a disappointing Spurs side into the lead at 1-0.
Spurs were largely bereft of ideas in the attacking third save for a curling first-time shot from Gylfi Sigurdsson (also signed this summer, from Hoffenheim) that edged over the bar and a good early cross from the Icelandic international that nearly picked out Gareth Bale.
Sporting the No. 11 this season—as opposed to the No. 8 he'd worn in campaigns past—Bale was one of a number of attacking Spurs players without much of an imprint on the first half (Jermain Defoe and Aaron Lennon were the others).
Norwich City boss Chris Hughton had inherited his side ahead of this season like his opposite number on the day, Andre Villas-Boas.
But where the former Newcastle United boss was concerned was in the defensive department—the Canaries scored the seventh-most goals of any side in the top division a season ago, so goals weren't the biggest problem. It was stopping them that was going to be Hughton's first potential imprint.
On Saturday, he got his tactics right in the first half. Dropping striker Grant Holt into midfield when they lost the ball, Norwich were able to snuff out any and all attacks from Tottenham in a first half they dominated for vast stretches.
Clint Dempsey and Hugo Lloris, brought in on transfer deadline day by Spurs Chairman Daniel Levy, arrived too late to play a part in Saturday's match.
Here's six other things we learned from the encounter.