Sunday's reverse top eight grid was again held in damp conditions with tyre choice being the critical factor. Brit William Buller opted to start on slicks and muscled his way from 25th on the grid at the start of the race to win by a comfortable margin.
Evans struggled on wets that went off in the drying conditions after an impressive start coming from seventh to battle for third on the opening lap. His tyre choice didn't pay off and, after spinning, he decided to pit for slicks.
But all was not lost, Evans' nearest rival in the race for the title, Vainio, also missed out on collecting any points when he fired into the back of Matias Laine's car, ending his race.
As the top two drivers in the championship failed to garner any points, Evans still has an 11-point buffer over Vainio with da Costa back in third a further 35 points behind. The next GP3 race is in Hockenheim, Germany, July 20-22.
Van Gisbergen fifth
New Zealand V8 Supercars driver Shane van Gisbergen put the dramas of Saturday, when he finished in 22nd, behind him for race two in Townsville at the weekend.
Though he could only manage the 18th fastest in the qualifying session for the second race on Sunday, the Stone Brothers Racing Ford driver crossed the line in seventh, earning enough points to ensure he didn't lose touch with fourth-placed Craig Lowndes, while still retaining a buffer of 41 points over Garth Tander.
Saturday race winner and 2012 series points' leader Jamie Whincup won Sunday's race from teammate Craig Lowndes with FPR's Will Davison in third.
"It was in the middle stint where I made a lot of time - the car was really good," said van Gisbergen. "I drove as hard as I could to get to seventh and, compared to yesterday, I'll take that over 22nd."
Fellow Kiwi V8 driver Fabian Coulthard remains in the top 10 in the hunt for the 2012 title in ninth. Porsche City Index Carrera Cup pilot Jonny Reid won his second round of the championship with a second and two firsts. The Kiwi is now third in the series behind Alex Davison and leader Craig Baird.
Dixon's nightmare
Kiwi IndyCar driver Scott Dixon must be wondering what's happened to his 2012 season. He's had a rollercoaster ride so far and the weekend's race in Toronto, Canada, was no different.
Dixon qualified well in third and was looking good to gain some more valuable championship points as the flag dropped. However, it was Ryan Hunter-Reay's day as he clinched his third win in the series to move him to the top of the points table. Dixon's day ended early on lap eight when his engine let go. The silver lining for the Kiwi was his main rival, Aussie Will Power, also came unstuck after he clipped Josef Newgarden's car and had to pit for repairs.
Dixon drops to fourth in the IZOD IndyCar series point standings on 281, 35 points behind leader Hunter-Reay.