Kenya's Jelimo and South Africa's Semenya hold their race bibs at a news conference in Ostrava (Photo: Reuters)
Jelimo, also the newly-crowned world indoor champion but who missed almost three years of competition after her Beijing Games triumph through injury, dominated the race to win in 1min 58.49sec, with Semenya in second in 2:00.80.
"The race was okay but the pacemaker was a bit slow," Jelimo said of Briton Dawn Hunt's opening lap time of 1:00.85.
"But I am satisfied with the result anyway. Of course everybody wants to do their best because it is so close to the Olympics.
"The windy conditions were the same for everyone," she said, adding that beating Semenya in particular had not been her specific goal.
"I do not run against anybody, including Caster. I just focus on myself. I want to try and do even better next week."
Semenya, with doubts over her real gender long buried in her past, left her push for the line too late.
The South African, who shot to fame when she won the world title in Berlin in 2009 but was then sidelined for 11 months during a probe into her gender, settled in at the back of the pack and only kicked with 150m to go.
By that stage, Jelimo had kicked and there was too much for Semenya, now coached by Mozambique running legend Maria Mutola, to make up.
"I'm feeling good," said Semenya. "I like hot weather, but I can't make the weather here an excuse. Congratulations to Pamela.
"I'm quite happy with my preparations for the Olympics. I now just need to build up more speed for competition.
"I was looking for a time under two minutes but I'm still quite happy with the race, even though my muscles didn't respond as I wanted them to because of the cold."
Semenya, likely to be South Africa's best prospect for gold at this summer's London Olympics, has said her goal was to replicate Mutola's podium-topping performance in the 800m at the 2000 Sydney Games in the British capital.
The South African, who also claimed silver at the 2011 worlds in Daegu, South Korea, will have her work cut out against Jelimo, who has regained her running form and confidence that deserted her after her triumph in Beijing.
"After 2008, I was exhausted," said Jelimo. "My coach was asking me what was the matter when he saw me in training. I needed to cut back. You have to respect what your body is telling you."
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