The Eagles, beaten only twice at home last season, had no answer as the team of Australian imports built on their impressive defence to run in tries from Anthony Wall, Phil Bergman and Wayne Sing.
Salford Reds made a winning start to their Super League campaign in a rare low-scoring affair. Phil Coussons' try midway through the first half was enough to give last season's First Division champions a 4-0 victory over Castleford.
The visitors thought they had scored midway through the second half when Tony Smith kicked ahead, but Simon Middleton had the touchdown disallowed when the in-goal touchjudge claimed he had bounced the ball.
A 40-yard sprint to the line by Adrian Morley sealed a deserved but hard- earned 32-22 home victory for Leeds against Oldham.
The teenage Great Britain forward burst on to a pass from Anthony Farrell as Leeds cashed in on the absence of Martin Crompton in the sin bin.
Leeds raced to an early 14-0 lead with tries from Richie Blackmore, Paul Sterling and Francis Cummins, who also kicked the first of his four goals.
Wayne Collins and Blackmore, with his second, added further touchdowns before Morley's decider, while tries from John Clarke, Scott Ranson, Crompton and Paul Atcheson kept the Bears in contention.