His performance yesterday proved a positive indicator that plans of being the third-best team are on track.
Rosberg making his move up the gears for Mercedes
The German's Mercedes-GP team endured a tough start to the new season with both Rosberg and his teammate Michael Schumacher being forced to retire at the season-opening race in Australia in March before finishing in the middle of the pack in Malaysia.
In Shanghai last month, Rosberg was fifth and Schumacher seventh, and the Brackley-based race outfit are hoping to build upon that momentum this weekend.
Rosberg said the team arrived at Istanbul Park looking to establish themselves as the third-best outfit behind Red Bull Racing and McLaren-Mercedes.
His performance yesterday proved a positive indicator that such plans are on track. While Schumacher struggled to find the necessary pace before placing eighth, Rosberg clocked a lap time of 1min 25.574secs to finish less than 0.6secs behind pole-sitter Sebastian Vettel.
"I'm happy for sure," said Rosberg, 25. "It's really nice to see the progress that we're making, when you think where we were four races ago.
"It's huge steps now and we're really learning from the mistakes and problems we've had. We're making the most of the car and extracting more and more from it."
Rosberg said not much has been changed on the car in the past few races, but that things are "just coming together".
"That's why I'm looking forward to what's to come now, once we get some upgrades. I'm pleased with third but, of course, we're still not where we want to be, so everybody's going to keep on pushing."
Having shown good pace in the morning practice session, Schumacher, 42, was predictably not so enthusiastic about his performance, explaining that "the more I pushed, the more things went wrong".
"I'm not happy at all" he said. "It didn't really work out at all. The grip for whatever reason wasn't there compared to what I had in the morning. The track certainly was better than it was in the morning but we couldn't reproduce what we did then. In the end there was no grip left."
In finishing third, Rosberg pushed McLaren's Lewis Hamilton back to fourth - the Englishman's lowest grid placing this season. Hamilton is aware he and teammate Jenson Button could now struggle to make an impact.
"Our biggest challenge could be getting off the line as every year here I've started on the dirty side," Hamilton said. "Mercedes have also picked up their pace, so it might be hard to overtake because they're very fast on the straights."