Saturday's victory in front of 4,000 vociferous fans, who made the short trip to Newcastle from Sunderland, was the crowning moment of Kelly's rollercoaster career.
The bout was a microcosm of his 20-fight journey in the ring. It was full of bravery and another tale of overcoming adversity.
Kelly entered the bout as an underdog and was written off by many before he'd even laced up his gloves.
It was not the first time he had been overlooked but unlike five years ago when he suffered a shock defeat and was battling with chronic hypochondria - the condition more formally called illness anxiety disorder - Kelly is now working with a reinforced mindset.
He came out confidently, knowing his coaching team, family and friends all believed he had the ability to prevail.
'Pretty Boy' danced around the ring and taunted the previously undefeated Murtazaliev before scoring a knockdown in the fourth round.
Murtazaliev rallied and responded with a knockdown of his own in the ninth but this was also something Kelly had experienced a premonition about.
"I was praying the other day and had a vision of me being knocked down in a round," Kelly said.
"I got back up and had these different feelings. One of them was that I got sloppy and lost the fight but the other was me getting back to what I do best and seeing through the round."
Kelly has come a long way from his mental struggles, which dovetailed with difficulties in making the weight when he fought at welterweight.
"I told everyone what I was dealing with at 147lbs (10st 7lb, 6.7kg), especially when it was Covid and I had health anxieties," Kelly said.
"I was telling my dad I was getting sick when I was in the hotels and always wearing a mask."
Kelly was tipped as a star of the future when he made his way through the amateur ranks and earned the chance to represent Great Britain at the 2016 Olympics.
In his first 10 fights as a professional, Kelly - who signed with promoter Matchroom - fought on cards at Cardiff's Principality Stadium, London's O2 Arena and Madison Square Garden in New York.
He was being pushed hard and delivering with winning performances.
But Kelly's dreams came crashing down after his loss against Avanesyan and he took a 16-month break before returning as a light-middleweight.
"I put Avanesyan to bed a long time ago," Kelly said. "I just had to believe in myself."
Now Kelly has the world at his feet.