Robert Kubica followed up Nick Heidfeld's runner-up position from Melbourne to cross the finish line behind Kimi Raikkonen in Sepang, as BMW Sauber continue to threaten favourites McLaren and Ferrari.
And Theissen sees no reason why the Hinwil-based outfit will be unable to achieve their ambitions for the season.
"Well, we have set two targets for this year," he said. "One was to turn the battle of two in front of us into a battle of three. And I think it looks like we are, at least in the two races so far, able to do that.
"The other target is to win our first race during the season. I am confident we can do that."
Theissen has said he is more encouraged by their actual speed in Malaysia than the result that keeps them second in the constructors' championship.
"I am pleased not just with the result, but also with the performance. Robert was able to settle behind the Ferraris right away after the start, and it was really good to see him doing so well.
"Nick was unlucky at the first corner, as he touched with Trulli. Both cars went wide, so several cars could slip by inside.
"They lost a lot of positions but he was able to move back up to sixth, doing the fastest lap at the end of the race and pulling off an overtaking manoeuvre (past Coulthard and Alonso) that was I think the best one of the race."
autosport.com