The New Zealand runner Angie Smit made the most of her opportunity in her first Diamond League race to finish fifth in the 800 metres in a packed London Olympic Stadium.
In a strong field Smit ran a time of two minutes 0.42 seconds, just outside her personal best set two weeks ago at the World Student Games in Russia.
After a quick first lap, Smit positioned herself well with a decisive move into fourth place with 200 metres to run.
She fought hard up the home straight, but was unable to climb into a top three position.
The race was won by the American Brenda Martinez in a meeting record of one minute 58.19 seconds.
Smit now returns to the New Zealand team's base in Berlin for her final preparations for the Moscow World Championships starting on 10 August.