But rookie Melbourne five-eighth Ryley Jacks threw a pass that bounced off two Brisbane defenders and into the arms of winger Addo-Carr for the try to lock up the match with Smith's conversion sealing the deal.
The Storm were seething in the 62nd minute when the bunker ruled Will Chambers had lost possession as he reached out to ground the ball on the tryline, however a different angle appeared to show the Melbourne centre maintained contact.
That try would have tied up the match.
Despite the Storm's late win, Cameron Munster broke his jaw after a head clash with Brisbane winger Corey Oates. Munster was forced off the field in the 60th minute.
Melbourne dominated possession and territory in the first half but could only manage an 8-6 lead, thanks to Jacks' first try in the NRL
.Melbourne coach Craig Bellamy started Slater on the bench, with Munster at fullback and Jacks at No.6.
Following Jacks' 22nd-minute try, Bellamy gave the crowd what they wanted, with Slater taking over fullback and Munster replacing Jacks.
Slater handled everything the Broncos threw at him and looked sharp in attack.
The Broncos took the lead in the second half via a brilliant individual try by halfback Ben Hunt, who dummied and then cut through some lazy Melbourne defence including Smith.
It looked like it would be enough for the Broncos but the Storm weren't to be denied.
