The manner of the home side's victory was a far cry from the 38-0 thumping they dished out to their neighbours at the same stage last season, in a tie that seldom lived up to its pre-match hype and bluster.
The Leopards had cancelled out French's opener through Robbie Mulhern, but trailed 14-6 at half-time after French's second try that was set up by man-of-the-match Jai Field, the former St George Illawarra and Parramatta star.
Although they sporadically threatened to reduce the deficit in the second half, Sam Walters flopped over on the final hooter to confirm the win.
Wigan will face either Hull KR or St Helens in the final at Old Trafford next Saturday and Peet paid tribute to the core group that has stayed largely unchanged throughout his side's return to domestic prominence.
"Toughness, I think, connection between the players ... these lads keep turning up for one another," Peet told Sky Sports.
"Jai Field a very special finals for him today, I'm not great in singling out people but Jai had a very good game.
"The kicks he was fielding, his cover tackle, he was just a handful with the ball all night, so I'm so proud of him on a night when people might question whether it was quiet for him.
"He's certainly developed that side of his game since he's been in the northern hemisphere."
Adrian Lam, the former Sydney Roosters star who also captained Queensland in State of Origin, was proud of his team.
"I thought we held our own for long periods of time in there," said the Papua New Guinean. "We felt we had three or four chances to score and we all agree that we needed to score in those moments.
"I'm very proud of them. What we've done this year is incredible and I'm very excited about what's ahead. It's difficult to feel it now but I think we're in a good place moving forward."
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