It was at a quarter to midnight that Anthony Joshua turned out the lights on Robert Helenius. Several minutes later, they finally came back on. The right hand came out of nowhere, hidden behind a pair of feinted jabs, and it turned the tide on a wave of boos in the O2 Arena, after the crowd had seemed to turn on Joshua. The Briton, 33, has been accused for some time now of being gun shy, but when he finally found the trigger on Saturday, he throttled it. It was killer instinct, coupled with god-given power, that allowed Joshua to rise through the sport quickly and impressively despite his late start. The ‘sweet science’ side of the game seemingly only appealed to him after he was stunned by Andy Ruiz Jr, and "AJ" employed elements of that approach in their rematch to construct a smart, safe performance and win on points. 'Safe' may just be the key word there, however, and it does hint at the downside to Joshua trying to add another string to his crossbow; that development also seemed to indicate a fear of letting loose – of risking ending up in a firefight. His interest in that tact increased after his first loss to Oleksandr Usyk, in which the Briton was discombobulated by the southpaw’s speed, angles and invention. Joshua tried to adapt in their rematch, but - although he improved upon his previous showing - he was outboxed again. It was only on the microphone, after the bout, that he let go. Similarly, it was only after the final bell in April, when Joshua had laboured past Jermaine Franklin, that there was any threat of a fight breaking out. On Saturday, Joshua was able to have his cake and eat it. For six rounds he probed patiently, to the audible frustration of the London crowd, but in the seventh round he finally produced the kind of one-shot KO that fans had craved all week, since Helenius was announced as Dillian Whyte's replacement. In the first round, Joshua found the timing of his jab quickly, to his credit. He varied its destination well, while his crosses and hooks were out of range for the time being. As the rounds progressed, however, those shots began to land intermittently, with Helenius more than once eating right crosses with his back to the ropes – a sign of what would ultimately prove his downfall. As early as the third round, fans had begun to whistle – then boo – but all the while Joshua kept working, refusing to force a finish. It could be argued that Joshua should have been more adventurous, mind you, but he was intent on taking his time. The lancing jab was still working to good effect, bloodying Helenius's nose badly. In the fifth, Joshua knocked the Finn, 39, off balance with a well-timed counter left hook, just as Helenius seemed to be growing in confidence, output and accuracy. But in the sixth, the boos resumed and reached a quite startling level, accompanied by one shout of: "AJ, what are you f***in' doin'??" Biding his time, it seemed, and in the next round he decided the time had come. Joshua jabbed low, then high, with neither shot landing but neither intended to. Behind those feints, Joshua hid a hard right cross, slung onto Helenius's chin, which sent the Finn lolloping sickeningly to the mat. Joshua walked away at once, knowing the job was done. Then, in a moment of defiance and with a glimmer of his old swagger, he turned and added a crotch chop, as the crowd around him finally used its voice to support the face of British boxing. “People need to leave me alone, let me breathe a bit. I’ll see you again soon, hopefully two more times this year, I need to stay busy,” Joshua said, before taking a shot at his rivals. “My back’s gone, I’m carrying this heavyweight division to the top.” Joshua, yet again to his credit, stayed to embrace those changeable masses in the O2 for more than half an hour. He has been accused of holding a grudge or two in his time, but he was quick to forgive on this night. Regardless of whether the Deontay Wilder fight is next for Joshua, the merit of this win should not be overlooked. Fans might actually cherish Joshua's come-up – that bewitching batch of knockouts against lesser foes – more than most of the fights in his two world-title reigns. When all is said and done, fighters leave fans with memories and highlights packages, and this victory over Helenius was a long-awaited, much-needed addition for Joshua. In winding back the clock, Joshua might just have found himself again. Read More Joshua vs Helenius LIVE: Boxing result and reaction after AJ delivers brutal knockout It’s time to stop taking Anthony Joshua for granted Campbell Hatton: ‘I used to have my nappy changed on the ring apron!’ Glove row put Anthony Joshua vs Robert Helenius in late doubt Anthony Joshua focused only on Robert Helenius amid Deontay Wilder speculation Anthony Joshua weighs in ahead of bout against Robert Helenius