The Chelsea star pounced on a mistake from Rui Patricio, who spilled Adrian Rabiot's shot into the former's path. Kante calmly tapped the ball home from point-blank range for his second international strike.
The Seleccao weren't poor; they created several half-chances, but lacked the cutting edge to finish them off, with Cristiano Ronaldo also missing a couple of good chances.
Les Blues will play their final fixture of the competition at home to Sweden on Wednesday while dethroned champions Portugal will be away at Croatia on the same day.
On that note, here are the five hits and flops from the match:
Hit: Antoine Griezmann (France)
Without Kylian Mbappe, the reigning world champions had to look somewhere else for goals, and Antoine Griezmann was supposedly the man to deliver. But he instead turned creator for the night, creating all of France's best moments with his ingenuity and expansive passing range.
The Barcelona star was a constant thorn in Portugal's flesh, flitting around in the gap between the hosts' midfield and defence to adroitly knit attacks together. Griezmann also sent in some excellent deliveries from set-pieces, one of which came off the crossbar after Raphael Varane headed it for Adrian Rabiot to shoot.
He ended the match with an 87% passing success and three key passes. While scoring one himself would've been the icing on the cake for Antoine Griezmann, he helped initiate Kante's winning goal and turned in a Man-of-the-Match performance.
Flop: Cristiano Ronaldo (Portugal)
The going has got really tough for Cristiano Ronaldo ever since he's broken the 100-goal barrier to edge closer to Ali Daei's all-time international goal-scoring record.
He fired blanks against Spain and France last month, missed the Sweden game because of COVID-19, came off the bench to score against Andorra in midweek and misfired against France once again.
The Portugal captain was back in the Seleccao lineup against the world champions but was left frustrated due to the lack of clear-cut opportunities. But that wasn't for the dearth of service, though. Ronaldo just couldn't connect with some of the crosses because they were either too high, or they didn't get to him inside the area, while his prowess at set-pieces also deserted him.
The Portugal captain has now gone almost 450 minutes without scoring against Les Blues, a poor record for someone of his stature. He'll have another opportunity to erase the anomaly at next year's Euros when the two sides will meet again, as both France and Portugal have been drawn in the same group. But for now, Ronaldo needs to focus on the next game for Portugal.