The South Korean forward benefitted from a Martin Dubravka error with seven minutes left as his powerful 20-yard shot went under the Newcastle goalkeeper’s body.
The away side were well organised and gritty throughout, with Fabian Schar’s acrobatic goalline clearance to deny Christian Eriksen in the second half epitomising their spirit.
Rafael Benitez’s side had chances of their own, with Salomon Rondon heading against the post with the score at 0-0 but their resistance was broken when substitute Fernando Llorente laid the ball off for Son to score a ninth goal in his past 10 Spurs appearances.
The win means Mauricio Pochettino’s side set a Premier League record as they reached 29 matches in a row without a draw, eclipsing Bolton’s mark of 28 set in 2011.
Newcastle stay 14th before the 15:00 GMT kick-offs.
Son and persistence win the day
Spurs’ lack of draws perhaps shows they refuse to settle and that has certainly been the case in recent weeks with late goals earning wins against Fulham, Watford and now Newcastle.
The snatching of such wins points to the kind of spirit Pochettino has needed from his players when faced with injuries to key names like Harry Kane and Dele Alli.
Perhaps no-one has stepped up more than Son.
His return from South Korea duty at the Asian Cup has proven key and just as fatigue looked to be setting in at Wembley, he found the space to win it.
It was the 14th goal he has been directly involved in during his past 10 Tottenham outings and ultimately moved his side above Manchester City – who play Arsenal on Sunday – and four points behind leaders Liverpool.
No-one had more shots than Son’s five but Llorente’s introduction from the bench on the hour was also pivotal as he served up the assist.
Spurs, with help from Dubravka, ultimately found an answer against a side who sat deep in a 5-4-1 formation and threatened in pockets on the break.
Given Lucas Moura headed wide from close range early on, Erik Lamela headed against the bar and Schar’s clearance from Eriksen, few could argue Spurs did not deserve three points.
Pochettino may not be happy that only four of their 21 shots hit the target but they got the job done for a third league win in a row.
Newcastle show promise in defeat
Their wing-backs – DeAndre Yedlin and Matt Ritchie – tucked in to make a narrow back five and Spurs were repeatedly forced left.
And with Rondon a presence up top they had chances of their own. He saw an effort blocked in the box and perhaps should have opened the scoring after the interval when his guided header hit the post with Hugo Lloris beaten.
Ayoze Perez also warmed the hands of the Spurs keeper from long range in the second period as Newcastle showed pockets of threat for their 28% possession.
They could have been better on the ball for periods, but Benitez will look at the dogged displays of Schar and Jamaal Lascelles as positives, along with the general resistance his side offered.
January addition Antonio Barreca came off the bench for his debut late on, while record signing Miguel Almiron was ineligible while he awaits a visa.
If the new £20m forward brings the quality fans crave, gutsy displays like this will at least give him a solid platform from which to perform.
More to follow.
- 6D Sánchez
- 11LamelaSubstituted forRoseat 78′minutes
- 7Son Heung-MinSubstituted forDierat 89′minutes
- 27Lucas MouraSubstituted forLlorenteat 60′minutes
- 22YedlinBooked at 65mins
- 11RitchieSubstituted forBarrecaat 86′minutes
- 30AtsuSubstituted forKenedyat 82′minutes
- Andre Marriner
Delay over. They are ready to continue.