Saturday brought Jacobson's career-best qualifying result of fifth and the 27-year-old's race pace looked mighty fine, but an incident during Sunday's endurance race put him on the back foot.
Jacobson took contact from Brodie Kostecki early in his stint after Dean Fiore had handed over the Nissan, damage that had him headed back to the pits for repairs to a bent steering arm.
And that was not all; after rejoining the race multiple laps down, his day would end early after a suspension upright failure.
A frustrated Jacobson, who now has just one race left with Kelly Racing before he departs at season's end, was disappointed he had not got the chance to show what the car was capable of.
“I had pretty light contact with Kostecki about three laps into my first stint after Dean jumped out of the car which bent a front left steering arm,” he said.
“I came into the pits and we got it fixed up, but I was three laps down by that point, still we had good speed, I wasn’t far off the times that (teammate) Andre (Heimgartner) was doing.
“Then for whatever reason we had a front right upright failure; it just wasn’t our day for reliability — we’ve had a pretty faultless car all year so it’s surprising, but these things happen in racing.”
He finished 22nd in his first race for the weekend, a disappointing day after starting 15th on the grid.
The results make Jacobson's bid for rookie of the year honours much tougher, now 126 points behind Macauley Jones.
Jacobson, who remains linked with Matt Stone Racing for a drive next year, took plenty of positives from the weekend, particularly the lightning-quick fifth position in qualifying.
“Overall I’m happy with the weekend, we qualified fifth which is by far the best result I’ve had and I’m starting to have pretty consistent top 15 results which I’m happy with considering where we’ve come from,” he said.
“It shows the momentum we have going into the end of the season, I wish we had more than one round left, I feel like I’m showing some good solid progress to move forward next year.”
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