Well that was a remarkably uneventful game.
Most pundits won't notice because of the two early goals, but essentially nothing happened there for 90 minutes. There was never any real threat that a goal would come from open play or even from a counter-attack.
That's not to say it was a bad game - just that neither side looked like breaking down the other and, with it being a cup final, neither team was prepared to risk anything to try and change it.
In extra-time Lazio didn't get luck and then they made a couple of mistakes, so they lost.
That's how games like that are decided.