A second close-range try came for the Eels with 10 minutes to go in the first half when Dave Taylor left a gap in the defensive line for Nathan Peats to dive over from dummy-half.
That gave the Eels a 10-6 halftime lead, but just as they were last week in Townsville against North Queensland, the visitors were overrun in the second 40.
Nene MacDonald scored a double inside seven minutes to put the Titans ahead, although his second try didn't come without controversy.
The video referee upheld the decision to award the try despite the suspicion Eels halfback Luke Kelly had got a hand between the ball and the ground.
Parramatta's Bureta Faraimo scored with a brilliant individual effort with 10 to go to threaten an Eels comeback.
Titans flyer James Roberts snuffed that out however when he picked up a spilled Eels ball and sprinted past Semi Radradra to score his fourth try against Parramatta this season.
Titans coach Neil Henry said the result was a relief after his team's recent poor form.
"It's great to get a win," he said.
"Two teams that are battling for a bit of confidence. Just happy for the boys.
"It's a relief but it's also showing that you can do things.
"We just need to play our footy."
The Eels, who lost centre pair Will Hopoate (hamstring) and Brad Takairangi (shoulder) before the match, head to Saturday's clash with Penrith in Darwin knowing their season is now effectively over.
Coach Brad Arthur didn't feel the result had wholly reflected his team's effort.
"I thought the boys tried very hard tonight," he said.
"We weren't beaten on effort, just our execution in attack let us down."
- AAP
