Running on empty as the toll of last week's brutal contest with Sydney Roosters, the Sea Eagles kept their season alive as the fast-finishing Sharks were unable to deliver the killer punch without absent playmaking star Todd Carney - second half tries to Andrew Fifita and Jonathan Wright leaving Cronulla just short.
Carney's absence was emphasised by a brilliant performance from Manly halfback Daly Cherry-Evans, who set up two tries and scored what proved to be the match-winner on the hour mark, but it was the intervention of Sharks' hooker Morris which proved just as crucial.
The Sharks looked like they had locked it up at 24-24 with seven minutes to go when skipper Paul Gallen charged over, only for the pocket referee to spot Morris taking out marker Matt Ballin as he attempted to make his way back to dummy half.
Gallen was in disbelief as referee Shayne Hayne sent the try to the video referee.
"Are you serious, I beat five blokes," Gallen said.
Morris played down the impact of his grab on Ballin.
"Hopefully that's not viewed as the thing that cost us in the end," Morris said.
"I was trying to get back to dummy half and probably realised I couldn't get there and pulled up."
The incident took away from what was a heroic Manly performance, but they face a mammoth task to back-up again next weekend from what has been a torrid first two weeks of the finals.
"I thought that they hung in there, I didn't realise how much last week took out of them to be honest with you," Sea Eagles coach Geoff Toovey said.
"After 20 minutes there was a lot of blokes out there that looked a bit tired but they did a job and I think Cronulla played some great football.
"They threw everything at us the last 15 minutes but we did really well to hang in there."
The Sea Eagles scored two first half tries - the first a fortuitous ricochet for Anthony Watmough - before Cherry-Evans laid it on a plate for halves partner Kieran Foran to score just before halftime.
When Jorge Taufua crossed three minutes after the restart to make it 18-6, the Sea eagles looked in control.
But the Sharks had reason to feel aggrieved with Taufua appearing to lose the ball - only for the video referee to deem there was insufficient evidence to overturn the ruling.
With the suspicion of a knock-on in the opening try, Sharks coach Shane Flanagan was obviously feeling hard done by.
"It's not going to change the result so I'm not going to go off my head, I'd like to - Noycey (chief executive Steve Noyce) hasn't got $10,000 and neither do I," Flanagan said, referring to the NRL fine for criticising referees.
Added Gallen: "I could sit here and talk conspiracy theories and give you something to write about for three days, (but) it's over, we were beaten.
"There's going to be human error, we had one thing go our way last week, we probably had three go against us tonight."