CARDIFF: Deep in the bowels of Cardiff’s Principality Stadium, Anthony Joshua sat with his four world heavyweight belts in front of him and called on Deontay Wilder to get serious about negotiations for a unification fight. Across the Atlantic, Wilder was posting a video on Twitter minutes later, shouting into his phone: “Joshua? Joshua? Stop playing, and pick up the phone!“ Team Joshua wants it. Team Wilder wants it. The boxing world and beyond wants it. But will it happen? The path was cleared for a fight between the sport’s two most destructive punchers when Joshua beat Joseph Parker in a unanimous decision in front of 78,000 spectators in Cardiff on Saturday. He added Parker’s WBO belt to his own WBA, IBF and lightly regarded IBO straps. Joshua paraded them in the ring. He displayed them in front of the world’s media. But he knows there’s one missing if he’s to become the first undisputed heavyweight champion since Lennox Lewis in 2000: Wilder’s WBC belt. “I will get all five of the belts,” Joshua said. “It’s not an issue.” Yet, he knows time is not on his side. And so does his promoter, Eddie Hearn. Being a multiple champion brings with it a range of mandatory fights. There’s only a small window for Joshua to clean up the division before the belts start getting stripped off him. “I think it has to happen in 2018,” Hearn said of the Wilder fight, “otherwise we are going to hit some major problems with the politics and the mandatories. It’s just a case of if it happens next or if we fight (someone else) in the summer and then Wilder. “If they stepped up and were actually serious about the fight, and serious about a deal we are more than happy to offer them, it could happen next. But they are so erratic and unpredictable, I don’t know what to believe.” It’s not the first time Hearn has spoken of the difficulties in dealing with Wilder’s people, and it likely won’t be the last. He has already visited New York for negotiations but it gets complicated with Wilder’s affairs being handled by co-managers Shelly Finkel and Al Haymon, and Haymon’s business partner Luis DeCubas Jr. Also problematic for Hearn and Joshua is Wilder’s apparent desire for a 50-50 split of any fight. Joshua believes, as a holder of four belts, that he deserves a bigger share of the pie. “I’m going to be one of the most powerful men sitting on the side of the negotiating table,” Joshua said, eyeing up his belts. “Why do I have to do all this work to have to give someone a bonus. Can I get a bonus now, do you know what I mean? Can I get a little pat on the back now? That’s how I see it. It’s a bit of a catch-22.” And that’s his problem. Joshua is in a rush to unify, but Wilder might not be. Much to their chagrin, Team Joshua might have to relent if their man is to reach his goal. Such is the demand for the fight that it will likely take place, perhaps a two-fight deal with one in America — where Joshua is yet to fight — and the other in Britain. Wilder has won all 40 of his pro fights (with 39 knockouts), while Joshua made it 21-0 with a no-frills win over Parker in which he showed another side to his boxing repertoire. Instead of his trademark big punches, Joshua used the jab behind his long reach to great effect. Parker was never allowed to get in close, either by Joshua or fussy referee Giuseppe Quartarone. It was a professional, mature display by Joshua against a previously unbeaten opponent, and it impressed his trainer Rob McCracken. “You’ve seen some of the heavyweights in the past win the fights behind the jab,” McCracken said, “and that’s what he did.” Joshua sees himself as more than just a big puncher, regularly referring his “finesse” and “boxing prowess.” He has spoken recently of the respect Floyd Mayweather earned for carving out an unbeaten career on the back of his technical skills, even if many of his fights weren’t spectacular. The problem is, fans flock in their tens of thousands to see Joshua pulverize his opponents. Just like Wilder does, admittedly in front of smaller crowds. It’s why the potential Joshua-Wilder match-up is so anticipated. Negotiations over the next few weeks will determine if that happens this summer.