The Olympic champion, whose career since that Beijing win has been blighted by injury, timed 1min 58.83sec for gold, Ukraine’s Nataliia Lupu taking silver in 1:59.67, with American Erica Moore claiming bronze (1:59.97).
“These last three years, with my injury were a disaster for me,” said Jelimo, who won at the Beijing Games at the tender age of just 18.
“Injuries have a great impact on top athletes.
“It was bad for all of us, my country, my management and me. But I did not give up and my coach motivated me a lot.
“It feels great to be a world champion, it’s great to be at the top again. I didn’t imagine winning this title.”
Jelimo was content to let Moore race out into the lead, biding her time in a physical run.
“There were a lot of pushes in the last two laps (on the 200m track), but that’s okay,” she said.
When Lupu pushed, Jelimo switched on the power and accelerated through to control the race through to the line well ahead of Lupu, with Moore scrambling over the line for bronze.
The 22-year-old said she now had one goal firmly set in her mind.
“I have to defend my Olympic title in London,” she said. “I hope everything will be okay and I stay healthy.”
Earlier, Bernard Lagat turned on the gas at the perfect moment to snatch a third world indoor 3000m title.
The Kenyan-born American was defending champion and also winner of the event in 2004 when racing for Kenya, but is now a relative veteran on the international circuit at the age of 37.
But that proved to be no barrier in an extremely high-quality field as the lithe runner broke for home with 100 metres to go and clocked a season’s best of 7min 41.44sec for a memorable gold.
Kenyan Augustine Choge took silver in 7:41.77 with compatriot Edwin Soi claiming bronze (7:41.78), one-hundredth of a second ahead of vaunted Briton Mo Farah, reigning world outdoor 5000m champion and silver medallist in the 10,000m.
“It feels so good,” beamed Lagat. “I played it safe. I just wanted to make sure I stayed safe, ie not getting behind position seven or so and remaining in reach of the two Kenyans.
“I was in my position and I was not going back. When Mo hit the front I told myself ‘I’m going with him’.
“With only four laps to go, it was easy for me. I knew it was now or never. I felt I still had enough energy.”
Lagat said the victory had been the perfect boost ahead of the London Olympics this summer.
“This is a great boost for my confidence,” he said. “I did it in Turkey and I know I can do it again in London.
“I might be 37 years old but my quick finish is not dying away!”
Choge took up the early running in the 15-lap event around the packed Atakoy Arena, with team-mate Soi, Lagat, Ethiopian world 5000m bronze medallist Dejen Gerbremeskel and Farah in their wake.
With three laps remaining, Farah hit the front, but the Briton’s pace and rhythm didn’t seem all there.
Choge hit back and was in the lead at the bell. But with half the final lap to go, Lagat accelerated to storm past a helpeless Farah.
Choge and Soi followed, but Lagat, with his eyes pinned on the big screen beyond the finish line and every sinew stretching, had enough to keep the Kenyan pair at bay.
The gold medal will be added to a collection that includes silver and bronze Olympic medals (1500m in 2000 and 2004) and a world 1500m silver in 2001 won for his native country before taking up US citizenship.
He went on to capture two golds for the US team in the 1500m and 5000m at the 2007 world outdoor championships in Osaka, Japan, followed by silver and bronze (5000 and 1500m) in Berlin in 2009 and another silver (5000m) in the Daegu worlds last year.