But the United striker's opener was ruled out by referee Chris Kavanagh after Scott McTominay's stray arm caught Son in the build-up.
Now, one football fan has revealed how costly that decision was when it came to their bet.
Twitter user JJ posted a £5 bet on the correct scorelines for three Premier League matches.
The punter correctly predicted Newcastle would beat Burnley 2-1 at Turf Moor and West Ham would secure a 3-2 win over Leicester City at the London Stadium.
Newcastle vs Burnley ending 2-1 was at 12/1 odds and West Ham vs Leicester finishing 3-2 was 33/1 odds.
But JJ's final bet was United would beat Spurs 4-1, which came in at 40/1 odds.
JJ's return from the £5 stake would have been a staggering £90,610 if all three of the bets would have come through.
Son fired Spurs into the lead in the first half only minutes after Cavani's opener was disallowed.
However, United bounced back in the second half as Fred, Cavani and Mason Greenwood scored to seal all three points.
The 28-year-old South Korean forward said: "I'm really disappointed this afternoon. I really don't know what to say. I'm really sorry about it and I feel bad.
"There's always been passion from outside, from this stadium -- and those who support us I know are really, really disappointed.
"I think they're even more disappointed than us, so feel really bad and sorry about it. A really sad afternoon."
Featured Image Credit: PA/Twitter
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