By Tris Dixon

SOME claim it was William Shakespeare who said “Expectation is the root of all heartache.”

Around 90,000 poured through the Wembley Stadium turnstiles on Saturday night clutching their priceless tickets in the immense hope that they were at one of those rare events, a huge fight that delivered on serious hype.

Millions in the UK and around the world tuned in with those same great expectations.

What followed, though, surpassed even the highest hopes as Anthony Joshua and Wladimir Klitschko rumbled in a heavyweight dogfight for the ages.

A pensive opening turned into a seesaw rollercoaster that saw momentum wildly shift one way, then the other, before Joshua finally burned down the Klitschko house in round 11. In doing so, he ascended to the top of the division and the summit of the sport.

Wladimir was dropped in round five only to rally viciously and have Joshua in dire straits when the Englishman appeared to punch himself out in pursuit of an early win.

The lead in Joshua’s legs bogged him down through the sixth and a pulverising Klitschko right caused the IBF champion to drop to the canvas for the first time in his career.

Klitschko assumed control. But, little by little, the frozen blocks that seemed to encase Joshua’s legs began to thaw. He dug deep. Then he roared back. A right uppercut that rung out through the annals of the heavyweight division jarred the great former champion’s head back dramatically in the eleventh and, two knockdowns later, the Ukrainian was saved from further punishment without protest.

It was a historic and miraculous blend of fun, excitement, violence and drama.

Joshua improved 19-0.

At 19-0 Mike Tyson was fighting James Tillis, George Foreman was facing 19-7-2 Aaron Eastling while Muhammad Ali was one bout from his first heavyweight coronation against Sonny Liston.

Joshua’s not there yet, obviously, but he’s walking in their footsteps.

They were just at the start of their journey then. Joshua now has the keys to multiple kingdoms as he and his braintrust decide upon which lucrative path to take next.

The show, the performance, the sportsmanship of both boxers almost made redundant the fact that two judges were preparing to give Joshua victory – when many felt the veteran was ahead – until that grandstand finish.

A superb result for boxing could have become a worldwide catastrophe had the wrong man won on the cards. The fighters didn’t allow the judges to steal their thunder. No one could, though the quiet, authoritarian impact of Joshua’s trainer Robert McCracken should not go unnoticed. What sets the ice-cool Birmingham man apart from his contemporaries is how his calm presence adds layers of reassurance to his disciples when they go into battle.

Let’s not forget here, either, what impact the late, great Emanuel Steward might have had on the other side of the ring had he been with Wladimir. A moot point, maybe, but surely Steward would have been proud of the qualities Klitschko finally showed, albeit at the end of his glittering career.

You need heart and guts to fight, that’s a given. You need balls the size of watermelons to do what Joshua and Wladimir did and yet the dignified grace with which Klitschko accepted the runners-up spot earned him an admiration that more than 20 emphatic title defences had not. The polite applause of the crowd signalled a genuine appreciation of what he left in the ring.

In defeat, he managed something he hadn’t in his entire Hall of Fame career; he’d never had anyone to share an all-time great fight with.

The man who’d previously been derided for not delivering entertainment because he dished out so many one-sided boxing beatdowns and pugilistic lessons played his part in a war that had more people on the edge of their seat in one night than they had been in his previous 68 contests. The words ‘Klitschko’ and ‘white-knuckle ride’ had never gone together, until last night.

Joshua has already won the veneration you get from an age-old ding-dong, completing what Eddie Hearn said was Phase Two of their four-phase plan. It had been an instant classic. The 27-year-old had ticked boxes that had been empty during his early career development. We did not know whether he could fight through real adversity, deliver on the biggest stage of all, climb off the floor, swim in the deep waters of conflict and hold his own in a shootout. Tick. Tick. Tick. Tick. Tick. Yes, questions remain. They always do.

As he negotiated the most treacherous 10 minutes of his career, fighting through the thrilling fog that descended upon him from deep in the fifth round until some point around the ninth, there was the feeling that matters could come to a disastrous climax for the Londoner.

Those who’d delivered good luck messages, from The Rock to Dr Dre, seemed set to shrivel back into their own high-profile worlds while Under Armour and Beats By Dre would have been looking for new cover stars.

During that visceral period, 41-year-old Klitschko boxed with a lucid, graceful swagger that he did not have in his twenties. The head movement was fluid, the footwork almost poetic and the ring generalship ridiculously articulate.

Yet, as Joshua should have deteriorated into the same oblivion so many Klitschko opponents have, either being ground into a late stoppage or demoralised into a points submission, he did something very different.

He caught a second wind.  There was no white flag of surrender. The pre-fight style turned into megafight substance. The carefully-polished brand was backed up by the brave, beating heart. He learned on the job. He visibly grew. He matured. He rose to the occasion and developed as a fighter before our eyes. His own robotic, tense stature relaxed and he dragged Klitschko back into that incredible pit of despair where it was his turn to be exhausted, vulnerable, confused and hurt.

And when he did have Klitshcko on the hook he did not let him off. Not this time. It was down to referee David Fields to do that.

People in boxing will always find a way to knock others down. Yes, he beat a 41-year-old Klitschko who’d been inactive. But that was a highly-motivated, top-drawer Klitschko, if you ask me, and I’ve been fortunate enough to witness many Klitschko fights over the years.

So the A-listers will continue to flock and call Joshua’s name. The Rock will wish him well again, Dr Dre has probably dialled in his congratulations and, sitting ringside, Arnold Schwarzenegger tweeted his delight at “One of the most exciting fights I’ve ever seen.”

Meanwhile, Wladimir has a tough decision to make, to fight on and try to earn a spot back at the top table or join his retired brother, Vitali, on the safer side of the ropes.

Unfortunately for him, Joshua came through his perfect storm and kicked the door in on superstardom, in the process spawning iconic images of a fallen Klitschko ‘bowing’ before him in surrender.

He’d grappled the torch from Klitschko’s grasp, something Tyson Fury did almost 18 months ago before flying off the rails. It’s all the more astonishing that he’s clearly a work in progress.

The expectations for last night had been unprecedented. Shakespeare would have had difficulty scripting what actually unfolded. Joshua, however, did not fluff his lines. Instead, he earned the part of unified world heavyweight champion, the face of British sport and the new face of world boxing.

That, however, is a hell of an act he must follow.

Whether it’s Tyson Fury, Deontay Wilder or even Klitschko again, the expectations could not be greater.