Ethiopian middle-distance star Genzebe Dibaba coasted through heats of the women’s 1500m on Friday.
The world champion, whose Somali coach was arrested in Spain in June as part of an investigation into drug trafficking, clocked a pedestrian 4min 10.61sec, more than 20sec slower than her own world record.
Dibaba’s teammate Dawit Seyaum, world junior champion in 2014, headed the times with 4:05.33.
Also qualifying for Sunday’s semi-finals were Britain’s Laura Weightman and American Shannon Rowbury.
The duo also competed in the 1500m at the 2012 London Games from which six of the top nine finishers have since been banned for doping.
“I am praying going into this championship that it will be a cleaner Olympics than before,” said Rowbury.
“Unfortunately that is out of my hands. I speak out because I want the federation to make changes and it does look like it is going that way. ”