For a few seconds, I am flat on the floor of the Opetaia Boxing Club, staring up at the ceiling.

That is what happens when you agree to take a half-cocked punch from Sonny Bill Williams, one of sport’s greatest specimens, straight into the ribs.

“Great session, mate!” he exclaims, as I lie on the floor, my gaze fixed on the SBW initials stitched onto the back of his shoes. Even with sweat clouding my eyesight, Williams still appears as if he’s sculpted from stone, perfectly honed and prepared for his heavyweight bout in Sydney next week.

Peeling myself off the ground, in a state of mild shock, we take a breather to talk rugby. What’s caught his eye?

“Henry Pollock,” the New Zealander starts, now a Sydney resident. “That guy is a powerhouse. He must be about 115 kilos (18st 1lb) but moves with remarkable speed. He’s strong, skillful. I admire what he brings to the table.”

“The Lions look formidable. Everything is clicking for them. Their squad is packed with champions, posing a real challenge for Australia. In the latter stages of the game, can they handle the Lions’ substitutes’ impact off the bench? I want to believe the Wallabies can rise to the occasion, but it really looks like a daunting challenge.”

Sonny Bill Williams (left) meets Mail Sport’s Nik Simon at Opetaia Boxing Club in Sydney

The former All Black hero is now a boxer, and will fight fellow former rugby player Paul Gallen on July 16

Williams was one of the great All Blacks and played in both World Cup-winning sides of 2011 and 2015

Williams was one of the great All Blacks, winning 58 caps from 2010 to 2019. But the 2017 Lions series brings back mixed emotions. We will get to his red card, which made front-page news across New Zealand, but his immediate focus is on the here and now.

Thud. Thud. Thud. At the end of his drills on the punch bag – overseen by coach Tapu Opetaia, father of world champion cruiserweight, Jai – he is joined by former team-mate Benny Robertson, who has a job to do.

Thud. Thud. Thud. Robertson repeatedly punches Williams in the abs to build resistance, explaining how they used to play rugby league together for the Canterbury-Bankstown Bulldogs.

Few players crossed rugby codes as successfully as Williams, although breakthrough Wallaby Joseph Sua’ali’i has been a box-office addition to the 15-man code in the last 12 months.

‘I’m really looking forward to the midfield battle in this series,’ says Williams. ‘I think Len Ikitau is a shoo-in for the Wallabies midfield, then there’s Hunter Paisami, so it comes down to where they decide to play Sua’ali’i. He’s a special talent. He’s better than me, doing his thing.

‘The hardest thing I found coming from league was that I was a forward in league and I had to go into the midfield in union. When you’re an outside back, a finisher, with that speed and those attributes, then you can go back and forth. I’d like to see Sua’ali’i out on the wings at the start, utilising his strengths under the high ball.’

It was in union where Williams enjoyed his prime rugby years. He was part of the all-conquering, double World Cup-winning All Blacks team from last decade – a team that became a symbol of sporting dominance, alongside the likes of Real Madrid and the Chicago Bulls.

‘Highs and lows,’ he says, when asked for his memories of the 2017 Lions tour, which ended with him being sent off for a dangerous hit on Anthony Watson.

Williams was shown a red card for this shoulder tackle on Lions winger Anthony Watson after just 24 minutes of the second Test in 2017

It was the first All Blacks red card for 50 years – since Colin Meads against Scotland in 1967 – and only the third ever

Williams scored in the Blues’ famous 22-16 win over the Lions earlier in the tour, and set up the match-winning try for Ihaia West late on

‘I remember all the stories that came with the Lions. People spending their whole life savings to come over. Rieko Ioane’s mother and father brought in someone that couldn’t afford a hotel. There were some cool stories. It was not only great for the economy and the country but rugby in general. It was massive.

‘When I was actually on the field, we did well. We beat the Lions with the Blues (22-16 at Eden Park), which was awesome, probably one of the high points of my career. In the first Test at Eden Park, we put on a really good show, then obviously the low point was when I got sent off. That was the first red for the All Blacks in about 50 years and we lost the game.

‘I got suspended for four weeks. These days I’d probably get suspended for 14. It was at the start of the game, and we’d trained putting pressure on them from the kicks, because the weather forecast wasn’t the greatest.

‘In my head I’m thinking, “I’m going to smash this guy, I’m going to put pressure on him and get a bit of momentum for my guys”. It was a red card, I just got it wrong.’

National news cameras gathered outside his disciplinary hearing in Wellington but it is now a distant memory. These days, Williams calls Sydney home. His wife is Australian so it is where they decided to settle with their five children.

Sydney is where this year’s Lions series will conclude, on August 2, and is also where Williams will fight Paul Gallen on July 16, bringing back that hit of adrenaline that he used to feel every weekend.

‘In boxing and rugby, if you can keep your wits about you then you’ll be better off,’ he says. ‘You’ve got to stay cool and stay calm. It ain’t easy. You’ve got to focus on your strengths.

‘If my knees were all right, I’d be able to jump back on the rugby field and handle myself because I know all the little subtleties.

Super-talented Williams crossed codes on four occasions, in 2008, 2013, 2014 and 2019 

Williams on the rampage against Mike Brown on the way to victory over England at Twickenham in 2014

Williams admits he was missing the pre-match nerves of top-level professional sport 

Williams sees some similarities between boxing and rugby, though he finds boxing far tougher

‘In the ring, it’s exactly the same, where to put your head, where to step… that comes naturally to guys who have done it all their lives.

‘So for me, boxing is way tougher, I’m pretty content with my life, five kids and what not. Did I really want to get back in the ring? If I did it, I was going to go all in, so that’s why I’m up here on the Gold Coast, away from the family. Two more weeks, I just want to get in there and fight.

‘The only thing I miss about professional sport is that nervous excitement in the sheds (the dressing room). The big events. You hate it but you love it. You get to that point where you climb or fall. That’s where I am right now.’

And that, you suspect, is exactly where the Lions and the Wallabies want to be over the next few weeks.