New recruit Holmes scored one try, tore away to help set up another and nailed three sideline conversions as the Dragons scored three times in six-and-a-half minutes to end Friday's contest by halftime.
Fighting to silence his critics, Dragons half Lachlan Ilias threw the last pass for Dylan Egan to cross late after helping put Tyrell Sloan over for his second try.
But it was Ilias' halves partner Kyle Flanagan setting up tries when the game was in the balance, Saints finally cashing in on a big lead after blowing two 12-point advantages in the opening five rounds.
Second-rower David Fifita had his best game of the year in a losing effort.
He threw the offload that led to Gold Coast's first try on the back of a poor pass from Ilias, and made a line break from a kick-off that led to their second.
The Titans will rue some poor edge defence and their inability to capitalise on their early chances, and have now followed two great wins with two big losses.
After withstanding two forced dropouts up 6-4, the Dragons marched upfield where bench forward Luciano Leilua put Holmes in for a try with a beautiful flat ball.
When Beau Fermor coughed up possession with a sloppy play-the-ball in the Titans' next set, Saints cashed in as Flanagan sent Tyrell Sloan over on the right.
Leilua and Holmes combined to open up a hole through the middle in the set after points, with Clint Gutherson passing off to Flanagan for yet another four-pointer.
The Red V had effectively ended the game going up 24-4 in their six-and-a-half minute blitz and restricted the visitors to only four play-the-balls in that time.
St George Illawarra must've known they'd as good as won the game after another Flanagan cut-out pass put Christian Tuipulotu over for his second try.
Tuipulotu reprised his "money" try celebration for the first time since being banned by coach Shane Flanagan on the grounds the Dragons weren't winning enough games.
The winger came from the field with a left hamstring issue later in the second half but made money gestures from the bench when Egan score his first NRL try.
The result means Gold Coast are yet to win a game in Wollongong from seven visits since their inception in 2007.