The NFL legend was in attendance at Old Trafford for the Premier League contest - to get a taste of some REAL football - and took to social media to celebrate CR7's stunning opener in the Premier League clash against Spurs.
After retiring from the game following a glittering career that lasted 22-years, Brady is now giving other sports a taste as a spectator.
And his experience of a proper football game came on Saturday evening as he sat in the director's box at Old Trafford to watch Man United take on Tottenham.
Before the game, he wrote on Twitter which side he'd be supporting, which might have come as a disappointment to huge NFL fan Kane.
"Here we go! @Cristiano vs. @HKane," the former New England Patriots and Tampa Bay Buccaneers quarterback said.
"I might fist pump if you score Harry but I'm riding with @ManUtd today."
Fortunately for Brady he didn't have to make a choice as both Ronaldo and Kane found the net.
CR7 netted a stunning goal to break the deadlock that brought a brilliant reaction from Brady on Twitter.
He posted a video fans would have loved, as it showed Ronaldo having a little giggle before saying his famous 'SIUUU' celebration.
Speaking on talkSPORT, former West Ham striker Dean Ashton was in awe of the strike.
"Woah," he said from the commentary box. "That is stunning from Cristiano Ronaldo! Absolutely stunning!
"It was a beautiful flick around the corner from Fred, Ronaldo got it out of his feet and it's a stunning, stinging strike that flashes past Hugo Lloris. The goalkeeper has got absolutely no chance.
"A beautiful, beautiful goal from Cristiano Ronaldo.
"You can tell a strike is beautiful when the ball doesn't move after it was hit. Wow.
"They say beauty is in the eye of the beholder, but I'm in love with that goal!"
Ronaldo wasn't done there, though, as he soon plundered his 806th and 807th career goals to become the highest scorer in football history - and got there in true CR7 style with a stunning hat-trick.
Empoli 
Udinese 
CSKA Moscow 
Rubin 
Slovan Bratislava 
AC Milan 
Sparta Praha 
Atletico Madrid 
Valencia 
Barcelona 
Stade Brestois 29 
Bayer Leverkusen 
Red Bull Salzburg 
Bayern Munich 
Paris Saint Germain 
Inter 
RB Leipzig 
Manchester City 
Feyenoord 
Sporting CP 
Arsenal 
FC Rostov 
Spartak Moscow 
Aston Villa 
Juventus 
Celtic 
Club Brugge 
Dinamo Zagreb 
Borussia Dortmund 
Liverpool 
Real Madrid 
Monaco 
Benfica 
PSV 
Shakhtar Donetsk 
Lokomotiv Moscow 
Dinamo Moscow 
Anderlecht 
FC Porto 
AZ Alkmaar 
Galatasaray 
Dynamo Kyiv 
Viktoria Plzen 
Lazio 
Ludogorets 
Qarabag 
Lyon 
FC Heidenheim 
Chelsea 
FC Midtjylland 
Eintracht Frankfurt 
Manchester Utd 
Bodo/Glimt 
Nice 
Rangers 
Real Sociedad 
Ajax 
Tottenham 
Roma