Rhasidat Adeleke faced a tough challenge as she competed in her first individual 400 meters at the Oslo Diamond League. Despite not being at her peak performance level with the World Championships in Tokyo approaching, Adeleke finished fourth with a time of 50.42 seconds, indicating that she still has room for improvement.

The race was won by US newcomer Isabella Whittaker in 49.58 seconds, with Henriette Jaeger from Norway setting a national record of 49.62 to secure second place. Although Adeleke started well and paced herself effectively, she was unable to accelerate in the final stretch, finishing outside her Irish record set last year.

Amber Anning overtook Adeleke in the last 50 meters to claim third place in 50.24 seconds. The lineup included several Olympic finalists from Paris last summer, showcasing a highly competitive field in the women's 400m event.

Whittaker, who recently graduated from college, expressed satisfaction with her season performance so far. Adeleke, who had previously competed in 200m races, faced her first true test in her specialist event at the Diamond League.

Following the Oslo event, Adeleke also competed in the 400m race in Stockholm, providing her with an opportunity to challenge the same opponents once again. Jaeger's impressive performance in Oslo, where she led most of the race before being overtaken by Whittaker, demonstrated the high level of competition in the event.

In a separate race, Mark English participated in a competitive 800m event and finished seventh with a time of 1:44.33. Despite his recent record-breaking achievements, English faced tough competition from some of the fastest men in the world, with Kenya's Emmanuel Wanyonyi claiming victory.

The cancellation of the Grand Slam Track series' final event in Los Angeles due to financial issues raised concerns, although co-founder Michael Johnson remains optimistic about the series' future in 2026.