A finalist interview is a different beast than other interview rounds.
New tactics are needed in order to secure the offer as the game has largely changed.
First, a finalist interview is no longer about determining whether you are qualified. They already know you have the necessary qualifications. Focus instead on what makes you uniquely qualified for it.
Second, it is more about the fit and which finalist they like the most. Numerous examples throughout time show a lesser experienced candidate surpassing the front runner at the end largely because they were better at pushing the emotional hot buttons of the interviewers.
Third, be prepared to compete. If you know you bring something to the table your competitor does not emphasize the importance of that area. Play to your strengths. Don't directly bash your competitor but clearly differentiate yourself.
Lastly, close for the offer. Ask for the job. Let them know you want it. It will move them emotionally when you say you want to be on their team.