After scoring a first win yesterday, and following a fine fifth in the reversed grid race earlier today, the factory-backed Honda driver found himself on pole for the finale.
A clean getaway helped him pull clear of fellow front-row starter Jay Hanson (Melbourne Performance Centre Audi), before D'Alberto settled into a 1.5-second lead.
On Lap 13 Zac Soutar (Team Soutar Motorsport Honda) passed Hanson for second and then set after the race leader.
But while Soutar was able to close the gap to D'Alberto he was never able to mount a proper challenge for the lead, D'Alberto scoring a second series win by just under four-tenths of a second.
"I'm just so relieved," said D'Alberto.
"We had a great car this weekend, we just tried to utilise it. I feel like we did everything we could.
"It's great for the championship and I'm just happy for Wall Racing and Honda Australia and everyone involved in our programme that gets us here. They've been believing in us for a long time and it's just nice to get some wins under my belt."
D'Alberto now holds a 58-point series lead with two rounds to go one, one at Sandown and another at Mount Panorama, traditionally not a happy hunting ground for the Civics.
"Every point is going to count," added D'Alberto. "We know we have an uphill battle going to Bathurst. We're just going to focus on one weekend at a time and I think we did a great job this weekend."
Hanson finished a somewhat lonely third place while Will Brown (MPC Audi) recovered from a first-lap run-in with Luke King (Moutai Hyundai) to finish fourth ahead of Bailey Sweeny (HMO Hyundai) and title contender Jordan Cox, who led the way for Garry Rogers Motorsport in his Peugeot.
King finished seventh, nursing some damage from being hit by Brown on that opening lap, ahead of Josh Buchan (HMO Hyundai), Michael Clemente (Michael Clemente Motorsport Honda) and Nathan Morcom (HMO Hyundai).
Michael Caruso, who was leading Race 2 earlier today until he suffered an engine failure, was a DNS despite the best efforts of the Ash Seward Motorsport crew to fit a new motor to his Alfa.
Sandown will host the next TCR Australia round on September 16-18.
