Interim Sharks coach Josh Hannay couldn't put his finger on why his team were abnormally fatigued in a Friday night loss to the Storm that could end their season.
After going into half-time at 12-12, Cronulla were overrun in the second term and went down 28-16 at Cbus Super Stadium.
They now need the Titans to lose to the Warriors - or win by fewer than 12 points - to advance to a seventh straight finals series.
Hannay said the Sharks would prepare as though they're playing next week with recovery and a review session on Saturday.
He wasn't sure as to why his troops were "out on their feet", speculating that arriving 45 minutes late to the ground after being stuck behind two accidents during their bus trip was a factor.
Match Highlights: Sharks v Storm
"If you look back at all our games, I don't know what it is – 20 minutes after half-time is for some reason our worst," he said.
"[Melbourne] just came out and ran hard. There was no sort of trickery to their start to the second half, their first try was just a barge-over try. [Marion Seve] ran harder than we were prepared to tackle.
"We fought hard but I thought – and I just spoke to the players about this - we just looked a bit tired and I don't know why.
"Statistically, it doesn't point to us having a reason to look tired. Possession, I think, was 50-50, but we looked out on our feet on both sides of the ball. We'll have to try and look at why that was."
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Despite the result, Hannay maintained a mostly positive outlook and said Cronulla are desperate to feature in the playoffs.
"We're disappointed. We wanted to go through the front door, not have to try and sneak through the back door," he said.
"It would've been nice to win tonight, but we've got a pulse. We'll hope and pray that things go our way on Sunday. Obviously, we'll be hoping [the Warriors] play the game of their life on Sunday."
Even if they ultimately finish ninth, there's been merit in a campaign in which the inexperienced Sharks have fought through adversity.
After the sacking of coach John Morris early in the year, Cronulla have battled on despite missing key players with a hefty injury toll.
"The resolve the young guys have shown, I think, is a good sign for the future because often the hardest part to coach into a young footballer is that resilience and that ability to hang tough," Hannay said.
"I thought tonight resilience and resolve wasn't what hurt us. I just thought their spine – and I highlighted this before the game and spoke about who was missing [for the Storm] - but their spine was still elite.
"Against our younger spine, I thought their spine showed their composure, their class, their experience, if you like.
"But our guys, it wasn't for lack of trying - they tried their backsides off. But we got probably punched a little bit tonight by the composure and class of their key players."
