British 400m hurdler Eilidh Doyle set a new personal best to win at the Diamond League meeting in Monaco.
Meanwhile, two-time Olympic champion Mo Farah came fifth in the 1500m.
Farah, who will defend his 5,000m and 10,000m titles in Brazil next month, finished strongly to clock a time of three minutes 31.74 seconds.
Compatriot Charlie Grice set a personal best, running 3:33.60 to finish ninth.
Doyle set the sixth fastest time in the world this year in the 400m hurdles, as she targets a medal in Rio. American Dalilah Muhammad is the only runner to have gone under 53 seconds, setting the best time of 52.88 in Eugene on 10 July.
Doyle beat the new European champion - Dane Sara Slott Petersen - and three Americans as she set a new Scottish record, beating her previous best of 54.22 she ran in Birmingham in 2013.
Lynsey Sharp came within four hundredths of her Scottish record as she finished sixth in one minute 57.75 seconds - her second fastest time - in an 800m won by South African Caster Semenya in a personal best of 1.55.33, a new national record.
Another Scot, Steph Twell, who will run the 5,000m in Rio, finished fifth in the 3,000m with a new personal best of 8.40.98.
The meeting took place just 15 miles from Nice, where at least 84 people were killed on Thursday.
A lorry struck a crowd marking Bastille Day in the southern French city.