For well over an hour, Tottenham's clash with Arsenal at Wembley was a rather tame north London derby.
Aaron Ramsey gave the Gunners a surprise lead after just 16 minutes and for much of the game, it was Unai Emery's side who were in control.
Spurs just weren't at the races on Saturday afternoon, but thanks to a rather controversial penalty call, the match burst into life with 15 minutes left.
Shkodran Mustafi was judged to have fouled Harry Kane inside the box as the striker challenged to get on the end of a Christian Eriksen free-kick.
Mustafi's challenge was clearly illegal - and no fans are debating that. But, many are arguing the spot-kick shouldn't have been given because Kane and a number of his teammates were offside.
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When Eriksen swung the ball in, it appeared that five Spurs players were standing goalside of the defensive line - check out footage from the match below.
Despite the evidence, the penalty was still given and Kane tucked it away well, leaving Arsenal fans fuming.
Many have been accusing Anthony Taylor and his linesman for wrongly making a game-changing call - but actually, the ref's decision to award a penalty was spot on, according to FA rules.
The laws of the game state that if "a player in an offside position is moving towards the ball with the intention of playing the ball and is fouled before playing or attempting to play the ball, or challenging an opponent for the ball, the foul is penalised as it has occurred before the offside offence".
So, Taylor was right to give the foul and actually applied the law perfectly. It seems to be a rather odd rule, but it's a rule nonetheless.
Although Arsenal will feel they deserved more than a point from the game, it's good to know that it wasn't Taylor who robbed the Gunners of a win.
Still, that probably won't soften the blow for the fans.