Bradford skipper Robbie Paul believes the Super League champions will have to develop a mental toughness to match their physical prowess if they are to retain their crown.

The Bulls launch their title defence tonight in the most difficult way imaginable with a trip to Wigan, the beaten Grand Finalists, and that, according to Paul, will set the tone for a season he likens to a marathon.

"Whenever you carry the tag of champions, every team you come up against have the underdog mentality and they want to beat you," he said.

"It will be the longest season of my career and it's going to take a lot of mental and physical energy to get through and be as dominant as we want to be."

Bradford have been installed as pre-season favourites to top the table and give themselves a head start in their bid to emulate St Helens, who achieved back-to-back titles with Grand Final victories in 1999 and 2000.

And Paul reckons the Bulls' emphatic Old Trafford win over Wigan, coupled with their recent notable triumph over Australian champions Newcastle Knights, removed once and for all their supposed fallibility on the big occasion.

"The real strength for us was that Grand Final win," he said.

"It taught us how to be a championship team; how to win big games and that was something this club had never had before.

"Before we carried the title of chokers but we've proved in two games that we don't choke.

"We know how to win big games and we're about winning. We know what it takes."

Paul is confident of leading the champions out at the JJB Stadium after resting the neck injury he aggravated in Bradford's shock home Challenge Cup defeat by Leeds three weeks ago.

Coach Brian Noble said: "He's had a full week of treatment and a full week's practice.

"I'm pretty confident and he's confident. I would say he's 90-10 in favour.

"But the lesson we learned from the Leeds game is that he won't play if he's not 100per cent."

Meanwhile, Paul expects Super League's traditional big four to be once more challenging for a place at the Theatre of Dreams in October.

Wigan are second favourites, with St Helens and Leeds also short-priced with the bookmakers.

Paul said: "The way it's shaping up, you would expect it to be the same clubs. Maybe Hull will be there again.

"It probably comes down to money and an ability to buy certain players.

"There is a big difference between the high-quality players of the world and the players that just make up numbers.

"You can see that the top four teams have recruited the big names."