SYDNEY (AP) — Souths moved atop Australia's National Rugby League with a 30-20 win over defending champion Melbourne in the weekend's 21st round, then hurried to rein in rising expectations of their title chances.

The Storm, who beat Souths 64-6 in Melbourne last year, came into the match on an eight-match winning streak and as established favorites to retain their premiership title.

Souths, in contrast, had mixed their form over the previous month with wins over the Bulldogs, Parramatta and North Queensland and a heavy loss to Wests.

An outstanding performance from hooker Damien Cook helped lift the Rabbitohs over Melbourne and to a two-point lead on the premiership ladder over the Storm and the Sydney Roosters, who beat North Queensland 26-20.

With Souths leading by only two points in the 63rd minute, Cook beat four defenders on a 40 meter dash to the line for a try that made the game safe. Cook finished the match with 176 running meters, six tackle breaks and a try assist.

Coach Anthony Seibold moved quickly after the match to keep fan expectations in check.

"We're pleased with the result and performance, there's no doubt about that," he said. "We're certainly not getting carried away. It's a good result for us but plenty of work to do.

"We'll review it, dump it and move on to our next job."

The win put Souths a match clear in first place of Melbourne and the Roosters. St. George Illawarra are a further two points back after an 18-12 loss to the New Zealand Warriors, the Dragons fourth loss in their last five games.

The Warriors, who only just held on to win after leading 18-0 at halftime, posted their eighth win in Australia this season, a club record.

The win also kept the Warriors safe inside the top eight, four points clear of Wests. The top eight is filled out by Cronulla, Penrith and Brisbane.