Cahill stunned Ronnie O’Sullivan in the 2019 World Championship after becoming the first amateur to qualify for the main draw.
Ben Mertens produced a fine performance to overcome James Cahill 6-2 in the first round of World Championship qualifying on Wednesday in Sheffield.
The Belgian youngster lost the opening frame but duly won the next five to establish a comfortable 5-1 advantage.
Cahill hung on with a break of 90, but Mertens held his nerve for a remarkable victory at the English Institute of Sport.
At just 15, Mertens becomes the youngest player in history to win a fixture at the World Championship.
Three further triumphs separate him from an unlikely debut at the Crucible Theatre at the end of the month.
The amateur first announced himself as a talented prospect with a first-round victory in the Paul Hunter Classic in 2018.
A subsequent defeat of James Wattana in last year’s Snooker Shoot Out brought him to the attention of a wider audience again, and it appears as though he is set to follow in the footsteps of countryman Luca Brecel and become a major star in the game.
💬 “The week can’t get any better!”
Belgium’s Ben Mertens was over the moon to get one frame, let alone six!
— World Snooker Tour (@WeAreWST) July 22, 2020
As well as Mertens, four other amateur players advanced to the second qualifying stage on day two.
Lukas Kleckers, who will be back on the Main Tour next season after his promotion from the Challenge Tour, benefited from the withdrawal of Sydney Wilson.
Veteran Rory McLeod, Ian Preece, and Jake Nicholson were triumphant after respective beatings of Billy Joe Castle, Igor Figueiredo, and Brandon Sargeant.
Meanwhile, a hectic schedule resulted in the first qualifying round being fully completed.
Experienced trio Barry Pinches, Gerard Greene, and Peter Lines all safely made it through their opening challenges.
For the latter, it keeps alive the exciting possibility of a winner-takes-all final qualifying round clash between Peter and his son, Oliver Lines.
Elsewhere, Hammad Miah fought back from 5-3 down and compiled a century break in the deciding frame to beat Austrian Florian Nüßle.
Malta’s Alex Borg and Chinese Fan Zhengyi were also made to work hard for their passages beyond Patrick Whelan and Dylan Emery – both ending with 6-4 scorelines.
It was easier for Fraser Patrick, who comprehensively saw off another hotly-tipped star of the future in Sean Maddocks, with Mitchell Mann and Simon Lichtenberg reaching the next round too.
On Thursday, the second round commences with the professional players ranked from 49 to 80 entering the fray.
For a lot of these competitors, like Irish duo Ken Doherty and Fergal O’Brien, victory will be essential in order to maintain their hopes of tour survival.