Mr Brightside's connection with the Champions Mile stretches back to when it was known as the Cantala Stakes and was run on Derby Day.
He finished fourth in that event in 2021, which was won by Superstorm, was third behind Alligator Blood and Tuvalu in the inaugural Champions Day edition in 2022 and beat home all-bar Pride Of Jenni in 2023.
He defeated star milers Antino, Fangirl and Stefi Magnetica in last year's Champions Mile, which was one of the highest-rating Group 1 races run in Australia last season.
Twenty-four of Mr Brightside's 47 starts have been at 1600m, for 13 wins, six seconds and one third, with his last placing in Hong Kong's Champions Mile in April the only time he has missed a quinella spot in his past 13 starts at the trip.
He and rider Craig Williams have the second-widest alley to deal with in Saturday's 10-horse race, which includes his King Charles III Stakes conqueror Ceolwulf (seven), Empire Rose Stakes winner Pride Of Jenni (two), Cox Plate placegetter Treasurethe Moment (three) and Doncaster Mile heroine Stefi Magnetica (one).
"It's a hard race to win and he's got some pretty stiff competition as well," Hayes said.
"There's some horses there that have beaten him before and he's also beaten them, so it's going to be a really interesting race.
"He's good enough, I know that, he's a special horse for us and we believe in him."