Team GB runner Lennie Waite has missed out on a place in the final of the women's 3,000m steeplechase, finishing one spot from last in the qualifying round.
The 30-year-old - British record-holder in the 2,000m distance - finished 47th from a field of 48 athletes with a disappointing time of 10:14.18 on Saturday morning.
Bahrain's Ruth Jebet was the fastest qualifier of the session with a time of 9:12.62, almost five seconds ahead of Kenyan runner Beatrice Chepkoech.
London 2012 silver medallist Habiba Ghribi of Tunisia was safely through in fourth place overall, closely followed by defending bronze medallist Sofia Assefa of Ethiopia.
The final of the event is due to take place on Monday morning at Rio's Olympic Stadium.