Jankovic needed just 83 minutes to secure her third title this year
New world number one Jelena Jankovic beat Nadia Petrova 6-4 6-3 to win the Porsche Grand Prix in Stuttgart.
Jankovic, who won last week's China Open, beat the Russian in 83 minutes to win her eighth career title and a red Porsche 911 presented by the sponsors.
The Serb was already assured of taking over top spot in the world from Serena Williams regardless of the result.
"That's two titles in two weeks and I'm back up to number one so obviously things are going very well," she said.
"I feel that every day I am getting better and better. I am really working on my game, I want to reach my full potential."
The 23-year-old needed painkillers before her semi-final win after tearing off a toe nail and had two more shots before the final.
They seemed to do the trick as Jankovic quickly secured the first set thanks to a single break in the Russian's opening service game.
The pair traded breaks in the second set before Petrova handed the advantage back to Jankovic with a wild backhand and the Serb powered through to clinch the title.
Petrova, who won the title in 2006, had not dropped a set before the final.
She said: "I went for every single point and tried everything I just made too many unforced errors and the key to playing Jelena is to be consistent."
Serena Williams became the number one after beating Jankovic in the final of the US Open, but the American will drop down the rankings after losing her opening match in Stuttgart.
Jankovic is signed up for next week's Kremlin Cup, although she left open whether she would actually show up in Moscow for the tournament, which Williams will miss.
"I feel tired now, but mentally I am not tired, I am hungry to do well. I want to finish the year as number one," she said.
Meanwhile, Romanian Sorana Cirstea, 18, secured her first WTA title by beating Sabine Lisicki of Germany in the final of the Tashkent Open.
Cirstea, the third seed, battled back from a set down to beat fourth seed Lisicki 2-6 6-4 7-6 (7-4).