Newcastle suffered their first home Premier League defeat since New Year's Day when Spurs emerged 3-1 winners at St James' Park.
United made the early pressing, with Miguel Almiron twice going close, while Allan Saint-Maximin saw a long-range shot pushed wide.
Jonjo Shelvey headed over from a perfect Matt Ritchie cross, before Dwight Gayle couldn't quite get on the end of a lovely pass from the United midfielder.
But it was Spurs who took the lead when defensive lapses allowed Son space the fire past Martin Dubravka.
Gayle came close to a leveller when he hit the post with a header late on in the half.
The equaliser came when Matt Ritchie pounced on a poor clearance to fire past Hugo Lloris with a blistering effort,
But Spurs immediately regained the lead when Harry Kane was allowed space to head past Dubravka.
And in the dying stages Kane added his second after Eric Lamela's chance was saved.
Martin Dubravka 6
On hand to keep Spurs at bay a couple of times but has no chance if his defence afford Kane that type of room to poise himself.
DeAndre Yedlin 4
Pushed high up the pitch in first half as a wing-back. Unable to produce a single cross. No surprise to see him taken off.
Federico Fernandez 4
Has had a few worrying displays in the last few matches. Newcastle badly missed Jamaal Lascelles to hold things together.
Fabian Schar 4
A terrible error to help hand Spurs a gift-wrapped opener.
Emil Krafth 5
Didn't do enough to prevent ball getting to Son for first goal. Not convincing in second half.
Matt Ritchie 6
Walloped home a fantastic equaliser but that was his only real highlight of the night.
Nabil Bentaleb 6
Tried to drive the side on with eight long passes forward. A big decision needs to be made on £8.6million fee and high wage packet.
Jonjo Shelvey 7
Can count himself unlucky after trying to create some good openings. A much better effort as skipper this time. Whipped in seven crosses.
Allan Saint-Maximin 8
Easily United's best player. Looks fantastic on the ball but sadly some of his team-mates aren't on same wavelength. Newcastle will need to build a team around him this summer.
Miguel Almiron 6
Had a go and can't be faulted for effort. Missed two big chances in first half.
Dwight Gayle 7
Worked hard and chased everything first half. Unlucky to see header hit post. Probably should have been left on.
Subs
Valentino Lazaro 7 (for Yedlin 55)
Helped create the equaliser for United. Decent show.
Joelinton 3 (for Gayle 68 mins)
Fans should expect much more from a Premier League striker - especially a £40million man.
Some poor touches.
Matty Longstaff (for Bentaleb 85)
Rate the players
Now it's your turn. Rate the players from the defeat to Spurs here.
We'll then collate the average score.
