Countdown is on.

Anthony Joshua comes face to face with Joseph Parker at yesterday’s weigh-in ahead of their fight in Cardiff tonight – the first heavyweight unification bout to be held in Britain.

Anthony Joshua will take inspiration from Floyd Mayweather to ensure he retains his composure when he fights to unify the WBO, WBA and IBF heavyweight titles tonight against Joseph Parker.

A 78,000-strong crowd is expected at Cardiff’s Principality Stadium where Joshua attempts to become the first to defeat WBO champion Parker in his first fight since those present at his victory over Carlos Takam booed through dissatisfaction at its conclusion.

The challenger that night for the 28-year-old’s WBA and IBF titles was rescued in the 10th round by the referee, before Joshua could secure a convincing knockout, and after he had become angered by Takam’s headbutts.

Victory over Takam followed that over Wladimir Klitschko, when Joshua risked defeat in pursuit of an early knockout, but despite external pressure to deliver the finish many expect this weekend, Joshua is determined to remain disciplined.

Given Mayweather preceded Joshua as the world’s leading fighter during a run in which he rarely won inside the distance, the Briton said: “You can’t always be trying to please people, because you’re never going to win.

“Mayweather, as great as he is, goes 12 rounds the majority of the time, and everyone claps and says how great the performance was, but because I don’t knock my opponent out in two rounds it’s a bad performance. Everyone’s got opinions.

“My job was to control Takam, move him around the ring where I wanted him, and secure the win so I could move forward to 2018, and that was a mature performance.

“I have to do the job for myself. It’s about performance, not just about going in there, looking for him and going ‘Bosh’ and hoping he flies out of the ring.

“My job was to perform, control the fight. He didn’t give me any problems apart from the headbutt, and people are looking past the boxing IQ.

“If you don’t knock an opponent out people are so interested in saying ‘He can’t punch, why didn’t he knock him out?’. Rather than saying ‘Did you see that left hook he defended, and came back? Did you see that uppercut?’ People aren’t interested in boxing IQ anymore. That’s why I study the game, because I respect that side of it.”

It was also widely felt that in last year’s dramatic victory over Klitschko, secured despite a relative lack of experience and which established his status as the world’s leading heavyweight, he performed like a fighter in his prime.

He has instead warned the 26-yearold Parker – who represents a more dangerous opponent than his status as a significant underdog suggests – that he expects to only begin to enter his prime, and also that he therefore expects to win between rounds seven and nine.

“You’re going to see me start priming, but I’m not in my prime yet,” he added. “When you see someone in your prime is when they stay at the top for four or five years, when you see someone getting to their prime, that’s what you’ll start seeing now.

“It’s him being humble, and not trying to be too over-confident (when he says he is yet to decide how to win).

“In my head I have to prepare for a 12-round fight, but if we’re talking about where it’ll end, I’m hoping to go somewhere between seven and nine.”

Joshua cut a lean figure on the Cardiff scales as he weighed in nearly a stone lighter than his last fight.

Joshua tipped the scales at 17st 4lb 2oz – 6lb heavier than his New Zealand opponent.

He had shed 12lb from his 18st 2lb frame when stopping Takam, while Parker has lost 9lb since outpointing Hughie Fury a month earlier.

“Taking that bit of weight off makes this fight a little easier,” Joshua said on stage after the two men had weighed in.

“I feel better. Training is all about rehearsal and so is sparring, but it has gone well.”

Parker is unbeaten in 24 fights and remains confident of upsetting the odds.

Parker said. “I’m here for war. You’ll have to do everything to beat me.”

Getty. Anthony Joshua greets fans at yesterday’s weigh-in in Cardiff.