In three of their first four sets, Thurston's replacement Michael Morgan fluffed his kick as Zillman and then Mark Minichiello crossed to open up a 12-0 advantage.
The Cowboys settled in to the match but had only Antonio Winterstein's four-pointer to show for it when Zillman broke clear in the 37th minute to send Albert Kelly over before an Aidan Sezer field goal made it 19-4 at halftime to the home team.
The Gold Coast fullback, taking over the leadership role with co-captains Nate Myles and Greg Bird on Origin duty, opened up a healthy lead when a clever inside ball by Dave Taylor sent him clear.
The Cowboys hinted at a comeback when Ashley Graham brilliantly snared a Clint Greenshields grubber and touched down in the corner just before going over the sideline.
But shortly after Minichiello was placed on report for a high tackle, Titans halfback Albert Kelly pounced on a loose Cowboys pass to run 85m and seal the win for the home side.
- AAP