Anthony Joshua added Joseph Parker’s WBO heavyweight title to his WBA and IBF straps (also IBO, if anyone cares about that) in his latest big stadium fight on Saturday.

Here are five key take-homes from Cardiff’s Principality Stadium.

1. AJ adds another dimension to his game

This fight was the first time Joshua went the distance, in his 21st professional bout. Not only will he not mind that fact, but going by the way Joshua and his team set up it appears they were more than ready for that fate.

A lean and trim AJ resisted Parker’s early attempts to lure him into expending energy early with a dangerously low guard, choosing to instead pick his spots and frustrate the New Zealander. Even though Parker seemed to have more success in the middle rounds, Joshua was far more in control than when he flagged during those same rounds of the Wlad Klitschko fight.

READ MORE: Anthony Joshua vs Joseph Parker – How the fight unfolded

IN PICTURES: Anthony Joshua v Joseph Parker

In fact, it was almost as if Joshua was channelling his inner Klitschko. It was another side to his game and one that will be more than useful if he does indeed take on the Deontay Wilders and Tyson Furys later on.

2. Wilder leaves money on the table, perhaps even shows his hand

Speaking of Deontay, he was invited to attend the fight. Boxers usually do that when they want to fight the winner. It’s a tried and tested way of getting the fight promotion started early and ensuring as many people as possible are clamouring for that contest to happen next. Unfortunately, despite claiming in interviews that AJ is “scared” of him, Wilder chose to stay in the United States and participate in their coverage of the fight.

The move makes no business sense. In fact, it only makes sense if Wilder has no interest in facing Joshua to unify the entire heavyweight division. We truly hope that’s not the case. Wilder needs this fight if he’s to prove himself once and for all. And the fans deserve it.

3. Shocking ref performance adds unfortunate asterisk

Giuseppe Quartarone was an interesting choice for this world heavyweight unification bout. And yet, when you think about it, an official with a tendency to break fighters prematurely every time they get close worked massively in Joshua’s favour when Parker’s gameplan was pretty much to rough up and tire his foe.

Quartrarone’s quirks occurred equally, cutting short big moments for both men. And yet, there was definitely one particular beneficiary to such an infuriating officiating style. It’s a shame as Joshua did pretty much everything right on his own, and such an appointment will now overshadow that to an extent.

4. Two world champions, two class acts

Let it be said that both Joshua and Parker are tremendous ambassadors for this sport, regardless of who won and who lost. In an age where some fighters feel obliged to swear, shout, threaten and sometimes even flirt with breaking the law to hype a fight, AJ and Joseph’s back-and-forth has been much more measured.

After the bout, both were respectful and even taking photos with the family of their opponent. Regardless of how the fight could have been more exciting or any other critiques, it’s worth remembering that much about both men.

5. Povetkin vs Price delivered exactly what it promised

The only notable bout on a tame undercard packed with promotional pet projects continuing their career progress, the chief support of Alexander Povetkin and David Price looked certain to be a truly uncomfortable contest and it was exactly that. A home hope in Price who always hits the canvas against a certain level of opponent going up against a former world title contender who has failed drug tests, hadn’t been subjected to adequate testing for this weekend and yet was still allowed to lace up the gloves and KO David in the fifth.

Everyone in boxing media has been unhappy with this scenario, and rightfully so. Legendary coach Freddie Roach recently said that Saul ‘Canelo’ Alvarez, who has failed a drug test ahead of a huge rematch with Gennady Golovkin, should be charged with attempted murder if he’s found to have deliberately taken performance enhancing substances. The same applies here – and Povetkin has previous.