The Storm celebrate a first-half try against the Panthers on Saturday night.

Clinical Storm outclass Panthers

The Melbourne Storm remain the only unbeaten side in the NRL and demonstrated why they're the league's leading defence, outclassing a determined Penrith Panthers side 28-6.

Aspiring premiership contenders Penrith were motivated to earn a landmark victory in Melbourne but the Storm held them scoreless in the second half, continuously repelling the many attacks on their own tryline.

Trailing 10-6 at half-time, the visitors spent much of the second half inside the opposition 20-metre zone but could not break the Storm's league-best defence.

Suliasi Vunivalu scored twice for the Storm while Cooper Cronk, Will Chambers and Josh Addo-Carr also grabbed tries, while Te Maire Martin scored the lone four-pointer for Penrith.

There was no repeat of last week's poor first-half showing from the Melbourne Storm, who enjoyed an enormous amount of possession on the Panthers' tryline in the first 20 minutes.

The home side opened the scoring when Will Chambers flicked a one-handed pass for Suliasi Vunivalu to cross in the right corner in the eighth minute.

Melbourne extended their lead with a second try down the right side with Chambers this time scoring himself. 

Chambers capitalised on a swift backline movement through Cooper Cronk and Cameron Smith to slip through the Panthers' defence to go ahead 10-0 after 20 minutes.

Despite a ruthless start for Melbourne, Penrith refused to be rattled and hit back 14 minutes before half-time.

A relieving penalty helped the Panthers march upfield, with Nathan Cleary setting up his halves-partner Te Maire Martin to crash his way over the try line.

The Panthers – growing in confidence – had several opportunities in Melbourne's half and crossed again but desperate Storm defence prevented Tyronne Peachey from grounding the ball.

The Storm quickly extended their 16-6 lead in the first minute of the second half, as Dale Finucane broke the line 40 metres out and offloaded for Cronk to score under the posts.

Sloppy errors creeped into the Storm's second-half effort, and the Panthers were desperate to convert their many second-half opportunities. 

Melbourne were rewarded for their resilience and patience as they added the penalty goal for a handy 12-point advantage with 20 minutes remaining.

In an inspirational second-half defensive effort, the home side sealed the game in the final 10 minutes when speedster Josh Addo-Carr raced away from a scrum for his latest long-range try down the left sideline.

Vunivalu's second-try in the final minute capped a superb win for the Storm, who retained their perfect start before next week's grand final rematch with the Cronulla Sharks.

Melbourne Storm 28 (Vunivalu 2, Chambers, Cronk, Addo-Carr tries; Smith 3 goals) def. Penrith Panthers 6 (Martin try, Cleary goal) at AAMI Park on Saturday night.