Unbeaten Melbourne celebrated a club-record ninth straight win as Penrith endured a 44-10 hammering as well as injuries to NSW State of Origin hopefuls Michael Jennings and Luke Lewis on Saturday night.

Star centre Jennings suffered a shoulder injury, while back-rower Lewis hobbled from the field at fulltime.

Adding to the Blues' growing injury list, Jennings was assisted from the ground minutes after Storm winger Justin O'Neill ghosted past him to run 90 metres early in the second half of the eight-tries-to-two rout at Centrebet Stadium.

The Panthers star originally suffered the injury to his right shoulder in last week's loss to Newcastle and looked a passenger until he was forced off in the 52nd minute.

The defeat continued Penrith's nightmare season with a fifth-straight defeat while Melbourne's victory and Brisbane's loss earlier on Saturday to the Warriors left the Storm four points clear at the head of the table.

O'Neill was brilliant for the Storm with a hat-trick of tries, including two outstanding long-range efforts.

He scored a 90-metre try on the stroke of halftime after great lead-up work from Billy Slater, who kicked through for the flying winger who touched down under the posts to make it 22-10 at the break.

Melbourne opened the scoring with a try to Matt Duffie on nine minutes before Penrith hit back with a four-pointer from debutant Josh Mansour, who produced a great finish on the left wing after a sweeping backline move.

The Panthers hit the lead soon after when replacement winger Etu Uaisele scored in the right corner to make it 10-6.

But Melbourne returned serve with tries to halfback Cooper Cronk and Ryan Hoffman before running away with the game in the second half with four unanswered tries.

- AAP