Last updated on .From the section Boxing

Former heavyweight world champion Oliver McCall, 54, has a record of 59 wins and 14 losses

"I want to fight Andy Ruiz Jr because he knocked out my son."

At 54, Oliver McCall is 24 years older than the man who took Anthony Joshua's IBF, WBA and WBO heavyweight titles in June.

But he has a family reason for wanting that unlikely contest to top off an extraordinary career - as his son Elijah was beaten by Ruiz in 2012, and retired soon afterwards.

McCall Sr made his professional debut in 1985, knocked out one Briton - Lennox Lewis - to win the world heavyweight title in 1994 and lost it to another - Frank Bruno - the following year.

In 1997, he stepped back into the ring with Lewis, only for the bout to be stopped in the fifth round when McCall refused to fight back and broke down in tears.

The day after the fight, the American said his actions had been tactical. However, it later emerged he had been admitted to rehab in the months prior to the bout because of his addiction to cocaine and cannabis. And two months after losing to Lewis, he was detained in a psychiatric hospital. external-link

Bruno retired in 1996, and Lewis in 2003.

But as the 25th year anniversary of that first Lewis fight approaches, McCall is still fighting - and he believes he has what it takes to become the oldest world champion in history, surpassing compatriot Bernard Hopkins.

"The older I get, the better I feel," he tells BBC Sport.

'Dad, you can do this'

McCall's greatest night in the ring came when he shocked Lennox Lewis with a second-round knockout

McCall knows he will be criticised for fighting into his 50s, but his goal is to prove people wrong.

"The trials and obstacles I have been through and overcome... I want to be able to finish the sport better than when I started," he says.

"I made sure my daughter, Shirley, came to watch me spar an undefeated heavyweight fighter a couple of months ago. I wanted her to see what I was able to do.

"She said: 'Dad, we are McCalls. You can do this.' The people who are close to me care about my wellbeing, but they can't believe what they see."

But will he get a licence?

McCall (centre) was in tears in his corner during his 1997 rematch against Lennox Lewis in Las Vegas. The referee stopped the fight in the fifth round and awarded Lewis the win after McCall refused to throw any punches.

McCall's second fight with Lewis was the 35th of his career. He was back within nine months and has fought almost 40 times since.

After losing to Marcin Rekowski in 2014, he was out of the ring for more than four years but returned to beat 27-year-old Larry Knight in November last year.

That fight took place in Corpus Christi after McCall was given a licence by Texas' boxing commission.

"Mr McCall meets the requirements set forth in the combative sports statutes in Texas, and a doctor cleared him to fight after conducting a physical examination," Tela Mange, from the Texas department of licensing and regulation, tells BBC Sport.

After beating Knight, McCall stopped home fighter Hugo Lomeli, 37, in Mexico in May - and plans to return to the ring once again by the end of the year.

McCall's manager Dr Chester Layne says it is possible the fighter may "run into problems" gaining a licence from other boxing commissions, but is confident they will overcome any issues.

"The state of Nevada, for example, will put him through some hoops, but that's fine. He's in peak physical condition," he says.

'I want to avenge my son's loss'

Mexico's Andy Ruiz Jr holds three of the four major world heavyweight titles after beating Brit Anthony Joshua in June

McCall's son Elijah was beaten by Ruiz in 2012. Now 31, he fought just twice more before retiring with a record of 12 wins, three losses and one draw.

McCall senior says: "After he knocked out my boy, I jumped in the ring and I looked at Ruiz and I said: 'Fight me.'

"That was years ago and it never materialised. But this will be a comeback story for me.

"I will be the only person in boxing history to avenge the loss of his son and become unified heavyweight champion. People will want to see that."

'Fury's the best - bring him on'

McCall believes Tyson Fury is the best heavyweight in the world at the moment.

The Briton is set to meet WBC heavyweight champion Deontay Wilder in a rematch in February.

At 28, he was born three years after McCall made his professional debut.

Despite that McCall says - in a somewhat tongue-in-cheek manner - he still fancies his chances.

"I know I will stop Tyson with body shots which will make his liver quiver and his whole body shiver," he adds with a grin.

How much longer will McCall fight for?

McCall defeated Hugo Lomeli in Mexico in May

As well as recapturing a world title, McCall has another goal in sight - to be boxing until at least 2 November 2020.

"It will be my 35-year anniversary of becoming a professional," he says.

"The major motivation for me is that I just love the sport of boxing.

"I want to make history."