Back in 2019 Cahill shocked the snooker world as he knocked out Ronnie O'Sullivan from the world championships. The 26-year-old has also picked up wins over the likes of Ding Junhui and Mark Selby at the UK Championship.
Putting on big performances against the big hitters has never been a problem for the man known as The Giant Killer. However, it's his performances against so called 'lesser opposition' that have held him back in recent years.
Cahill is looking for a return to the World Snooker Tour after dropping out in the culmination of the 2020/21 campaign.
While he failed to come through Q School 12 months ago, he is certainly making decent progress in this week's event.
After establishing a 2-1 lead over O'Donnell, the Englishman produced breaks of 78 and 61 to seal his place in the fifth round, where he'll take on Ross Bulman.
Joining him in the next round will be former Snooker Shoot Out champion Michael Georgiou. The 34-year-old was forced to come back from 2-0 down to seal his 4-2 victory over Daniel Womersley - picking up breaks of 51 and 61 along the way.
His next opponent will be Andrew Higginson who defeated Ukraine's Iulian Boiko 4-1 during the morning session.
Elsewhere, another former Snooker Shoot Out champion, Michael Holt, survived an edgy affair with Sean Harvey.
Holt went 2-0 down before winning the next three frames. Harvey levelled things up to take the match to a decider, but ultimately it was the former world number 20 who kept his cool and prevailed.
Belgian teenager Ben Mertens enjoyed a 4-0 whitewash victory over Alfie Davies, while Germany's Lukas Kleckers picked up a 4-2 win over Ross Muir.
Daniel Wells, meanwhile, produced breaks of 112 and 62 as he knocked out former world number 32 Rory McLeod.