SYDNEY, July 27, 2008 (AFP) - Shock defeats by premiership contenders Manly Sea Eagles and Melbourne Storm gave the Sydney Roosters the chance to make up some lost ground in this weekend's Australian National Rugby League.

The Roosters bolted to an 18-0 lead in the opening 12 minutes on the way to upsetting competition leaders Manly 34-12 at the Sydney Football Stadium on Sunday.

Defending champions Melbourne Storm relinquished their chance to join Manly at the top of the standings when they stumbled to an 8-6 loss to the New Zealand Warriors in Auckland on Sunday.

The Roosters picked up two competition points to join the Storm on 28 points, two points behind the front-running Sea Eagles after 20 rounds.

The Roosters' victory was virtually assured with a 24-6 halftime lead and any chance of a Manly comeback was doused after the break by a torrential downpour and winger Amos Roberts' stunning second try of the afternoon.

In Auckland, a 40-metre Lance Hohaia penalty goal with eight minutes left earned the Warriors an unexpected 8-6 victory to stretch their winning streak to four matches.

With controversy simmering after a week of criticism of Melbourne's on-field wrestling tactics, the Storm were put under pressure from a resolute Warriors defence and turned the ball over regularly in wet conditions.

Cronulla lost ground in an 18-12 loss to a much-improved Brisbane Broncos in Brisbane on Friday.

Broncos utility Greg Eastwood scored the match-winning try eight minutes from time to put the game out of reach of the fast-finishing Sharks.

Brisbane, who had several of their leading players returning from injury, moved up to 25 points, three behind Melbourne, Roosters and Cronulla.

Penrith climbed to sixth spot after a 24-10 victory over Wests Tigers at home on Saturday.

The Panthers came from behind for their four-tries-to-two win, but they may have paid a price for the victory with highly-rated rookie Lachlan Coote suffering suspected medial knee ligament damage.

St George Illawarra Dragons can leapfrog Penrith on the standings if they can win their home game on Monday against the Canterbury Bulldogs, reeling after the sensational walkout of New Zealand Test forward Sonny Bill Williams to French rugby.

Canberra put behind trouble of their own to demolish Gold Coast Titans 46-4 at home on Saturday.

All week the media had focused on the Raiders for all the wrong reasons after star scrum-half Todd Carney was suspended for the rest of the season after another drinking misdemeanour.