Suliasi Vunivalu celebrates his early try against Penrith on Saturday night.

The Melbourne Storm outclassed a determined Penrith Panthers side 28-6 to stand as the NRL Telstra Premiership's only undefeated side.

Storm's resilient defence

Resilient. Tough. Brave. Gutsy. There aren't enough ways to describe the Storm's incredible defence. 

After last week's uncharacteristically sloppy performance, defence was the focus for this week's clash against the attack-minded Penrith Panthers. Not only did Melbourne accomplish the key goal, they delivered in a huge way to fight off a determined Panthers side. 

Coach Craig Bellamy was thrilled with his side's defensive effort. Despite a lopsided tackle count of 403-300 and Penrith dominating 60 per cent of possession, the Storm held their opponents to a single try in the first half and a second-half shutout. 

Trailing 10-6 at halftime, the visitors had a plethora of opportunities, camped inside Melbourne's 20-metre zone for the majority of the second half. However, the Storm held the mountain men scoreless in an 18-0 second-half domination on the way to a highly-impressive 22-point win.

Young Panthers a work in progress

While the Storm's defensive effort was outstanding, the Panthers showed why they still have plenty of room for improvement to be counted as one of the NRL's premiership contenders. 

A bitter 14-12 loss to the Sydney Roosters before last week's 40-0 thumping of the Newcastle Knights left the Panthers determined for another opportunity to prove themselves against last year's grand finalists and minor premiers Melbourne. 

Young halves duo Nathan Cleary and Te Maire Martin tried hard all night and combined for a nice play short of the line for Martin to cross in the 26th minute. However, there were several instances and fifth-tackle options that coach Anthony Griffin lamented. 

To exacerbate the Panthers' lack of execution, the efficient-and-experienced Storm made the most of their opportunities behind their "Big Three" of Cameron Smith, Billy Slater and Cooper Cronk. 

Lopsided record

Storm head coach Craig Bellamy couldn't explain the historical head-to-head record against the Panthers in his side's favour earlier this week but whatever it is, it's working for the Storm. 

Following Saturday's result, Melbourne have won 25 of their 32 clashes with Penrith. 

In the past 18 encounters, the Panthers have only won once in Round 9, 2013. Moreover, it was their seventh-straight loss at AAMI Park. 

With no other match-up with Melbourne in the regular season, and while it's a long way away, if Penrith are to achieve their premiership dream, they will mostly likely come across the Storm again in the finals series.

Last undefeated team

The Storm remain the NRL's only unbeaten team with a perfect 5-0 start. 

The 2016 minor premiers haven't missed a beat this season. 

Despite a grueling opening fixture travelling to New Zealand and Sydney twice, Melbourne prevail no matter the situation whether they're trailing in late game finishes, poor first-half starts or wet weather. 

They've beaten legitimate top-eight sides in the Brisbane Broncos and the Panthers, and claimed tough road wins against the Canterbury Bulldogs, Warriors and an under-the-pump Wests Tigers last week. 

Their perfect record will be put on the line, as the Storm face a stern task against the reigning premiers the Cronulla Sharks in a grand final rematch at AAMI Park next Sunday.

Grand Final rematch

While Storm skipper Cameron Smith said his side has put last year's devastating grand final loss to bed, there's no doubt there would be some sort of satisfaction in beating the defending premiers, the Sharks. 

Melbourne are hell-bent on premiership redemption this year, and defeating Cronulla would help exorcise any mental demons languishing from 2016's excruciating disappointment. 

The Sharks were far from impressive in their last-gasp 19-18 win over the Newcastle Knights earlier on Saturday and will need significant improvement to hand the Storm their first loss of the season. 

It's sure to be a heated affair in a tense showdown.