Super League champions Bradford Bulls warmed up for their World Club Challenge with a comfortable victory in the Gary Mercer testimonial match at the Jungle.

The full-strength Bulls looked rusty at times on their first run-out since their Grand Final triumph three months ago but did enough to send out a warning to Australia champions Newcastle Knights ahead of their clash at Huddersfield's McAlpine Stadium on Friday week.

They were given a testing work-out by a lively Castleford side and coach Brian Noble, who used no fewer than 25 players, will have been relieved to avoid serious injury.

Captain Robbie Paul, who scored two of his side's six tries in a sparkling display, went off after 60 minutes with a gash to his head but should be fit for his face-to-face confrontation with Knights skipper Andrew Johns.

The kick-off was put back 15 minutes to let the 2,000 delayed Bradford fans through the turnstiles and their patience was quickly rewarded.

Most eyes were on Bradford's big close-season signing, the 6ft 3in, 15st 7lb Lesley Vainikolo, nicknamed the 'Volcano', and he lived up to his nickname by exploding into action after just three minutes.

The 22-year-old Tongan-born New Zealand international raced onto a kick from Paul Deacon, plucked the ball from the grasp of opponent Jon Wells and showed a clean pair of heels to full-back Richard Gay before touching down.

It was a dream start for Vainikolo, who was playing his first match for eight months following a chest injury, but the big winger did not see much more of the ball and was brought off 15 minutes from the end.

Bradford relied on their customary forward strength but were also indebted to the dazzling skills of Paul, while Daniel Gartner and James Lowes were at the heart of a tremendous defensive display.

Castleford took a shock lead with Michael Smith's close-range try on 20 minutes and half-back Mark Lennon caused problems with his darting runs.

But the Bulls were generally on top, however, and a Lee Gilmour try helped them to a 16-6 interval lead, while substitute Paul Sykes grabbed two second-half tries and Paul Deacon kicked three goals.

The Tigers gained some consolation in injury time when centre Andy Johnson, one of three new signings on view, scored his side's second try and Wayne Bartrim kicked his second goal.