Korea Republic forward Son was on target in the first half with a free-kick that he surely intended to be a cross at Tottenham Hotspur Stadium on Sunday.

Son's goal in his landmark top-flight game was enough for Spurs to go into the international break at the summit, with the only 100 per cent record after three matches.

Tottenham, which had Harry Kane in the starting line-up for the first time domestically this season after he opted to stay at the club, has not conceded a top-flight goal in 2021-2022 amid a promising start to Nuno Espirito Santo's reign.

Watford fashioned a good chance to take an early lead in an entertaining start, but Eric Dier got his head in the way of a shot from Juraj Kucka after he was set up by former Spurs midfielder Moussa Sissoko, who was making his debut for the Hornets.

Daniel Bachmann kept out a shot from Japhet Tanganga after a Spurs corner before a combination of Dier and Sergio Reguilon thwarted Joshua King at the other end.

Tottenham was not posing much of a threat until Son whipped in a free-kick from the left that evaded everybody and found the far corner of the net.

Watford lost captain Craig Cathcart to injury early in the second half, but it had opportunities to equalise when an unmarked Kucka fired off target before Ismaila Sarr's shot from close range was blocked by Davinson Sanchez.

Spurs came close to doubling their lead with a rapid counterattack, Son surging forward and laying the ball off to Kane, whose inviting pass was drilled wide by Dele Alli.

Sissoko was given a great ovation from the Tottenham fans when he was substituted just a couple of days after leaving the club, and Pierre-Emile Hojbjerg's deflected free-kick was palmed wide by Bachmann a few minutes later.

Brilliant defending from William Troost-Ekong denied Kane a tap-in and Bachmann kept the England captain at bay, but Son's goal was enough to put Nuno's side top.