Rohit Sharma-led Mumbai Indians clinched the IPL trophy for a third time.
Mumbai Indians had lost all the three matches against Steve Smith's side in the league stages.
Tripathi's story started with going for the trials held by IPL franchise Rising Pune Supergiant (RPS) at the DY Patil Stadium in Mumbai.
Mumbai leg-spinner Karn Sharma took four wickets to bowl out KKR for a paltry 107 in 18.5 overs.
Mumbai Indians will now take on Rising Pune Supergiant in the final on Sunday.
Mumbai rode on Karn Sharma (4/16) and Jasprit Bumrah's (3/7) brilliant bowling effort to skittle KKR out for 107 inside 18.5 overs.
Australia will start their Champions Trophy campaign against New Zealand in Birmingham on June 2.
Gambhir is happy that some of his players still remember the grief of the 22-run defeat they suffered last year.
MS Dhoni smashed five sixes, taking Mitchell McClenaghan and Jasprit Bumrah to the cleaners.