The former England hooker, 33, scored three tries to lead the Exiles to a semi-final victory against Doncaster.
Irish now need to beat Yorkshire over two legs to seal promotion and an immediate return to the Premiership.
"Playing rugby when there's something really meaningful on it really lifts us as players," Paice told BBC Sport.
The two-legged final, which starts at Headingley on 17 May, sees the top two in the regular season face each other for promotion.
Irish lost just once on their way to the top of the table, while Yorkshire will hope to give head coach Bryan Redpath the perfect send-off before he departs the club.
"We're coming up to the two biggest games of my career, the club's career and the season," Paice admitted.
"I've been lucky to play in a couple of big games, but this is right up there. We'll have to deal with the pressure we're going to face, but we're looking forward to it.
"Yorkshire, like Doncaster, are a big forward pack but have lots of threats behind the eight and a dangerous back three if you give them a lot of the ball."
David Paice believes London Irish's Championship play-off final against Yorkshire Carnegie will be "the two biggest games" of his career.