Anthony Joshua's self-belief is growing but he insists he retains the spirit of an underdog despite being widely regarded as the number one heavyweight in the world.

Joshua will attempt to strengthen his claim to that status when he puts his WBA and IBF titles on the line against WBO champion Joseph Parker at Cardiff's Principality Stadium at the weekend.

This will be Joshua's sixth world title fight in only his 21st professional outing although, speaking at last night's open workouts at St David's Hall, he is not about to believe in his own hype.

"You still need to keep that challenger's mindset. I'm still the challenger in my head," the Watford fighter said to Sky Sports.

"Sometimes I try and not be seen with the belts too much, I let other people do the enjoyment because I've got to do the challenger mindset.

"I'm looking forward to the challenge of Parker but, just because now I'm the hunted, it's not time to put my feet up and relax, I'm out there defending my throne on Saturday night."

Joshua has captured the British public's imagination after following up his London 2012 gold medal by stopping all 20 of his opponents in the paid ranks.

This bout against New Zealand's Parker will be his third successive stadium fight and around 80,000 fans are expected to be under the roof of Wales' national stadium on Saturday night.

With a glittering record and his ever-expanding popularity behind him, the 28-year-old says his confidence is improving.

He said: "Physically I've always tried to prepare myself the best way. Not only that, I'm starting to believe in myself which is important. I'm believing in my ability, I'm focused."

Responding to Parker's earlier claim of a "war", Joshua responded: "It's silly, it's boxing.

"In boxing I'm hearing all you need is a good chin and a right hand but we've been working on finesse, technique and counter-punching, so I hope Joseph Parker falls into my booby traps because I'm going to set him up for some power shots as well."

Parker conducted his workout prior to Joshua and, while clad all in black, was quick to remind the assembled crowd of New Zealand's dominance over Wales in rugby union - with the Kiwis winning all 10 of their encounters in the Principality Stadium.

He said: "The All Blacks always do great here in Wales so I'm looking forward to keeping that record clean."

Parker (24-0, 18KOs) repeated a recent claim that he and his camp have been able to irritate Joshua in the build-up, adding: "I think some of the things our team have said has got under his skin, he looks a little angry and tense.

"I'm young, hungry, fit and strong. I've got my speed back and I'll show you on Saturday."

Asked whether he had a final message for his opponent, he said: "I'll see you soon, let's go to war!"