That's the view of England lock Ollie Chessum, who has hailed the former Wallabies coach for his impact at the Midlands club.
It is set to be a summer of change at Welford Road, with former Leicester player Geoff Parling, the ex-Wallabies assistant, to take charge after Cheika departs at the end of his one-year contract.
Just a couple of seasons on from their last Premiership final triumph, the Tigers finished eighth in a disappointing 2023-24 campaign.
The arrival of Cheika - who took the Wallabies to the 2015 World Cup final and then guided Argentina into the last four two years ago - saw Leicester's fortunes transformed.
On the back of a new-found mental resilience, Cheika's men were driven on to second place in the table behind Bath.
Chessum, who fought his way back to fitness following a knee injury suffered in an England training camp in October, feels 58-year-old Cheika deserves plenty of plaudits for helping turn the club around.
"We were in a real good spot a few years ago as a group, and we probably lost our way a little bit and that is how you find yourself down in eighth and out of the play-offs," said Chessum.
"There is no denying that something needed to change in quite a few aspects of our game.
"Cheiks will say we have probably not changed too much technically, but it is just around that mental side and the emotional side of the game is what has really changed everything this year and has put us in this spot."
Chessum, 24, added: "He just finds a way to galvanise the group, get them to find a real meaning in what they are doing and use that to to drive them on. Our mental approach for the team has changed massively towards games.
"He will say that goes a huge way towards winning, it is just believing you can do it and sort of shocking yourself really with what you are able to do as an individual.
"The way he has changed how the team approaches the game mentally has been a huge part of what he will leave as a legacy."
Cheika has named an unchanged side from the semi-final win over Sale for Saturday's final at the Allianz Stadium, which will see several Leicester players make their last appearance in a Tigers shirt.
Club stalwarts Dan Cole and Ben Youngs will retire while captain Julian Montoya, South Africa fly-half Handre Pollard, James Cronin and Matt Rogerson are all set to depart.
Leicester lost home and away to Bath during the regular campaign, beaten 43-15 at The Recreation Ground in May.
Chessum knows the Tigers will have to step up to the challenge as Bath seek to complete a trophy treble with what would be the Somerset club's first league title since 1996.
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