Four-time champion Mark Selby is on the brink of crashing out of the World Championship at the first hurdle after losing the first session of his first round match 7-3 to debutant Joe O’Connor.

Selby, who questioned his future in the sport after losing to Gary Wilson in the Tour Championship earlier this month, was second best against his Leicester rival, who reeled off five frames in a row to leave himself in a commanding position ahead of Monday’s resumption.

The 40-year-old Selby has endured a dismal season by his standards, reaching one ranking tournament final and two semi-finals, but has traditionally reserved his best form of the season for the Crucible.

Despite sharing the opening two frames, Selby looked distinctly out of sorts and two centuries in three frames sent O’Connor three frames clear, before two further half-centuries sealed a sensational debut performance from the 28-year-old.

O’Connor, who has previously tried and failed seven times to reach the Crucible, is the only debutant in this year’s field, and requires just one more century on Monday to equal the record for a first-time performer at the venue.

Eleventh seed Zhang Anda followed defending champion Luca Brecel out of the tournament as he was hammered 10-4 by last year’s surprise quarter-finalist Jak Jones.

Resuming 5-2 in front after their abridged opening session on Saturday, Jones chiselled his way over the line with a top break of 60, while Zhang’s 95 in the 13th frame proved much too little, too late.

Jones, who beat Neil Robertson last year en route to the last eight, will face either fellow Welshman Mark Williams or last year’s surprise semi-finalist Si Jiahui in round two.

Ronnie O’Sullivan eases into the Crucible on the hunt for a modern record eighth world title and it is abundantly apparent that if the Rocket is in the mood, then very few of his rivals will be able to live with him.

But while O’Sullivan continues to soak up all the pre-tournament column inches, the PA news agency sizes up the best of the rest who are left with the daunting task of putting the brakes on the best player the game has seen.

Luca Brecel

Barring a run to the final of the non-ranking Shanghai Masters, Brecel has done anything but build on his stunning title success last year, and must rank as one of the least fancied returning champions in history. But the Belgian was equally unfancied 12 months ago when he waded into the Crucible insisting he had not laid a hand on the practice table, so it feels wrong to write him off entirely just yet.

Judd Trump

Flashback to 2019 when Trump’s maiden world crown bore all the hallmarks of a decade of dominance ahead. No fewer than 14 ranking titles have followed – including five this year alone – but with the exception of the 2023 Masters, the coveted majors have remained elusive. Trump undoubtedly has the talent to become a multiple world champion, but whether he has the temperament to see it through again remains a significant question mark.

Mark Selby

Four-time winner Selby trudges to the Crucible on the back of another inconsistent campaign that left him seriously considering retirement after his loss to Gary Wilson in the first round of this month’s Tour Championship. All of which will count for nothing, of course, when the Crucible kicks back in and the 40-year-old, who has repeatedly showed the tenacity to grind his way through the rounds, will once again be well and truly in the running.

Mark Allen

Seemingly in danger of becoming known as one of the game’s great under-achievers, Allen radically altered his style a couple of seasons ago and the ranking titles began rolling in – five in the last two years, plus a Champion of Champions gong. While it undoubtedly makes him better-equipped to break his Crucible duck, the fact remains that his Crucible record – with just two semi-finals in 17 appearances – leaves a lot to be desired.

Gary Wilson

Wilson’s run to the 2019 semi-finals as a qualifier looked to have been a flash in the pan until the last two seasons, in which the Tyneside man has picked up three ranking crowns and established a reputation as one of the toughest match-players in the business. With a steady temperament that makes him well-suited to the long game, Wilson could emerge once again as a major threat.

Barry Hawkins will return to the Crucible this year convinced he has proved a point to those who questioned whether he still had the hunger to pursue a second appearance in a World Snooker Championship final.

Hawkins’ relatively serene progress within the game’s elite – peaking with his 2013 final loss to Ronnie O’Sullivan – was rudely interrupted last year when he dropped out of the top 16 and failed to qualify for Sheffield the first time in 17 years.

But while the 44-year-old admits he too started to doubt his ability to return, a stellar current season, capped by his ending a seven-year wait for a fourth ranking title at the European Masters in August, will send him back to Sheffield in good heart.

“I know sometimes I come across like I’m not hungry enough, but it must be in there somewhere or I wouldn’t have been around as long as I have,” Hawkins told the PA news agency. “You need that hunger or you’re not going to succeed.

“I was devastated to miss out last year and for my run to come to an end. I don’t think I’ve ever felt so low about snooker.

“Inevitably, when you’ve played in ranking finals and massive arenas, your ranking starts to drop and you can’t help but start wondering if you’re on the slippery slope to retirement.

“It’s hard to keep that sustainability and that mindset, but I got my nose back in the top 16 and I set my goal to be seeded for the Crucible. I’ve bounced back this season and after winning the title in Germany I feel like my game is in good shape.”

Hawkins evolved into one of the Crucible’s most consistent performances in the wake of his run to the 2013 final, embarking on a run that would see him reach four semi-finals and one quarter over the next five years, including an epic 13-12 second-round win over O’Sullivan in 2016.

But his seemingly effortless progress belied a story of gritty resilience for the mild-mannered Hawkins, who failed to reach Sheffield for nine straight years before booking his place at the 10th attempt in 2006 – only to lose 10-1 to Ken Doherty.

“My immediate reaction was, thank God it’s over,” recalled Hawkins. “I was only young and I was completely demoralised, but at the same time I remember coming off and thinking, ‘I want to get back in there’.

“I couldn’t have imagined that I was going to go and play there so many times, have some unbelievable runs and beat some of the greatest players. It seems like a distant memory now but I suppose it did toughen me up for what was ahead.”

One of only a handful of current players to have proved he has the stamina for the 17-day Crucible slog, Hawkins, who is also a two-time Masters finalist, has renewed hope that could crown his career with a coveted ‘triple crown’ title.

“As the years go by the belief slowly dwindles that you are going to win one of the big ones,” he added.

“But you’ve just got to keep punching and live in hope, because you never know when it could happen. It could come completely out of the blue.

“One thing’s for sure, if I finish my career and I haven’t managed it, it won’t be through lack of trying.”

Ronnie O’Sullivan may claim not to care about records but the magnitude of his quest to eclipse Stephen Hendry and claim a record-breaking eighth world snooker title in the modern era cannot be understated.

O’Sullivan heads to the Crucible as reluctantly as ever, yet he is arguably never in a stronger position to go one better than his great rival and further enhance his surely unarguable status as the greatest snooker player of all time.

It is a mark of his true greatness that O’Sullivan finds himself in such a position at the age of 48, and having adopted an almost lackadaisical public approach to his sport, picking and choosing his events and constantly deriding his own performances and occasionally those of his peers.

While other players sweat and toil and chisel their way deep into the Crucible’s 17 days, O’Sullivan will waft in and out with an agenda led by the prospect of lucrative exhibitions and ambassadorial deals with the likes of Saudi Arabia, further underscoring his status as simply a player apart.

There are a handful who have proved themselves more than capable of sinking O’Sullivan – not least his fellow ‘Class of 92’ star Mark Williams, who routed him 10-5 in the Tour Championship final last month and is exhibiting some of his best form in years.

Mark Selby, despite another torrid season which resulted in him recently threatening retirement, still summoned a rare 6-0 whitewash of O’Sullivan in February, while emergent Chinese star Zhang Anda beat him in back-to-back tournaments earlier in this campaign.

Yet it remains abundantly clear that having withdrawn from no fewer than seven ranking titles this season for various medical and mental health reasons, the biggest threat to O’Sullivan clinching that prestigious eighth title remains O’Sullivan himself.

Snooker is still waiting for a true rival to stand up and be counted. Judd Trump continues to sweep all before him in lesser ranking events but his displays in the so-called majors have left much to be desired, the expected surge after his 2019 world title win having hardly materialised.

Luca Brecel, the reigning champion and a man after O’Sullivan’s heart after swaggering into the Crucible last year to win the thing despite insisting he had not so much as potted a ball in practice, has endured a dismal season by any top-16 player’s standards.

Selby is another to have performed sluggishly but his grit and determination invariably makes him come good at at the Crucible, and he is clearly the name to be reckoned with – qualifiers notwithstanding – in a much weaker top half of the draw.

Mark Allen is another whose undoubted talent has seldom been glimpsed in a series of Crucible calamities, while older stagers like Ali Carter and Gary Wilson have the guts but perhaps not that final special something required to go all the way.

Two players who were shaping up into the best prospects to at least share the spotlight with O’Sullivan and haul the sport into a new global era, Zhao Xintong and Yan Bingtao, remain banned for a variety of offences relating to betting on snooker.

It is 90 years since the great Joe Davis won his own eighth title, beating the only other player willing to stump up the five guineas entry fee, Tom Newman, 25-22 in the final played over five days at Kettering’s Central Hall.

In those intervening years the game has changed unfathomably, to the point where Saudi princes are dangling the lure of seven-figure prize money for players who pot a golden ball at the end of a maximum break.

But one constant remains: the dominance of a single individual. Not since the great pioneer Davis, who would go on to win 15 straight titles before retiring undefeated in 1946, has the sport seen a player so far apart from the rest of the field.

The latest episode of the Ronnie O’Sullivan show starts this weekend – whether O’Sullivan, or the sport’s officials, or the rivals he leaves so consistently short-changed and occasionally enraged – like to see it that way or not.