Sharks winger Valentine Holmes makes a break against the Storm in Round 4 of the Telstra Premiership.

Melbourne Storm coach Craig Bellamy was left wondering what had happened to his side's legendary ruck defence following Monday night's 14-6 loss to the Sharks at Southern Cross Group Stadium. 

In a low-scoring affair, the Sharks scored both of their tries through Melbourne's usually impenetrable middle-third, with Ben Barba and Valentine Holmes making a mockery of the Storm ruck with blistering speed.

It's an area of the game Bellamy didn't expect to be beaten, but the Storm mentor has vowed to rectify the situation with immediate effect. 

"I can't remember the last time the Storm have had all their tries against us come through the middle of the ruck," Bellamy said after the game.  

"That just hasn't happened in the 14 years I've been here and that's really disappointing for me.

"It was just a couple of lapses. They didn't make a whole heap of breaks through there. We know Holmes and Barba are quick, so perhaps we need to be a little bit more on guard. It's not what we're about, and it's not what we've been about. 

"We need to get over this pretty quickly. We'll try to improve the areas we need to improve and hopefully be a bit better next week."

It wasn't all doom and gloom according to their coach, with Bellamy particularly pleased with the way his side handled the sin-binning of Will Chambers early in the first-half. 

However, Bellamy also conceded that his side had fallen back into bad habits from 2015, namely not playing for the entire 80 minutes. 

"We probably struggled from the start," Bellamy said.

"There were some real good parts. In that second half they had the ball on our line a lot and in the first half when we had 12 men we really dug in and defended really well.

"But we had some really ordinary parts too. It was a real mixture, which is a little bit of us from last year. 

"Game to game and being inconsistent, that was one thing we didn't want to be. We wanted to be consistent and we certainly weren't that tonight. That was the disappointing part for me.

"They out-enthused us, they out-aggressed us, they outworked us and they out-disciplined us as well. It wasn't a great night for us."

It wasn't just Melbourne's defence that was off, with captain Cameron Smith left to rue some poor fifth tackle options, including two of his own kicks that went into the backs of Cronulla players.

Given it was their first loss of the season, there is certainly no need to panic, but Smith says he wants to see a vastly improved performance when they face the Knights on Saturday afternoon.  

"There were a couple of times in our attack tonight where things just broke down," the Storm skipper said. 

"I don't think it was a lack of effort. We had plenty of work defensively to do tonight and I don't know, maybe we were a bit gassed at the end. There are a lot of things we need to work on in our attack."