Joseph Parker is in an ideal position to break down Saturday’s rematch between Andy Ruiz Jr. and Anthony Joshua, as he fought both men in heavyweight title fights.

Parker, who was born in New Zealand but trains in Las Vegas, won the WBO world heavyweight title with a majority decision over Ruiz in 2016 — Ruiz’s only defeat to date.

After two defenses, Parker lost the title via unanimous decision to Joshua in March 2018, which left Joshua in possession of three of the four major world titles.

But Joshua (22-1, 21 KOs), 30, lost the belts and his unbeaten record when Ruiz (33-1, 22 KOs), 30, from Imperial, California, dropped him four times in a seventh-round stoppage win at Madison Square Garden in New York in June, ending Joshua’s reign after six defenses.

Ahead of Ruiz-Joshua 2, Parker gives us his firsthand insights into both fighters, and explains what Ruiz has to do to retain his titles, as well as what Joshua needs to win them back.

How Joshua wins

Since the loss, I’ve seen Joshua has trimmed down a lot, and in his training he has done a lot of moving around the ring. He has height and reach advantages, and if he boxes Ruiz with those advantages, and boxes smoothly, then he can win comfortably on points. If he can punch Ruiz well on the outside, Joshua can drop him. Remember, Ruiz had never been dropped before Joshua knocked him down in Round 3 of their first encounter, so Joshua knows he has the power to do it.

How Ruiz wins

Ruiz is the sort of fighter who piles on pressure, and if he has had a complete training camp this time, as we have been led to believe, then he’s going to be able to put even more pressure and throw a wider variety of punches than he did in the first fight. Ruiz has been saying he’s going to put more punches on Joshua and that he will try to put on constant pressure.

Ruiz punches very hard and has fast counter punches. I think he was too heavy before, but he has trimmed down too, and his team is trying to give him more speed in the rematch.

What’s the biggest thing Joshua has to improve in the rematch?

He needs to box from the outside, and use his natural advantages. Joshua will have to be able to cope with Ruiz throwing a lot of punches at him, but that will create chances. If Joshua is careful, he can pick his moment.

When I fought Ruiz, I caused him trouble with my movement, which made him miss a lot of shots, or they were just grazing shots so they didn’t have the effect on me that they had on Joshua. Joshua could do the same — move and make Ruiz miss.

Joshua needs to box better on the back foot in this fight. Before he fought Ruiz, in a lot of his fights he had been the one going forward.

Parker’s prediction

It’s intriguing because we don’t know which way it’s going to go. Both look trim.

If Joshua loses, where does he go from there? If Ruiz loses, it could lead to a third fight, and we know Ruiz is no joke. I knew it before he fought Joshua, but now the world knows it. People were saying he didn’t look in shape before the first fight, but they underestimated him. I was surprised how he finished the fight, though, and it shows that anything can happen.

I will have to go for Joshua … but it’s not going to be easy.