It was a rather cool start to the meeting between Blåvitt and Sirius at Gamla Ullevi, where Blåvitt had a couple of scoring chances that resulted in nothing.
Marcus Berg also got a good position after 40 minutes, but the sharpness of the shot was lacking.
But when the 36-year-old got another chance a couple of minutes later, after taking down a long ball from debutant Salaou Abundance, he made it 1-0 with a confident right foot at the far post.
Shortly after the half-time break, the former national team player would be back again.
Both he and goalkeeper Tommi Vaiho ran towards the ball, but Berg reached first and was able to poke it in just behind Vaiho.
Sirius managed to take over part of the ball possession in the second half, but without relying on the safe blue-white defense and the match ended 2-0 to the home team.
Berg is third in the scoring league with a total of eleven goals for the season.
He returned to IFK Göteborg last season after over a decade as a professional abroad.