Jessica Ennis-Hill is in pole position at the end of the first day's competition in the women's heptathlon.
The defending champion from London 2012 began the day strongly in her preferred event, the 100m hurdles, with a session-best time of 12.84s, before managing a height of 1.89m on the high jump.
Ennis-Hill looked to be losing her grip on first place with the day's third event, the shot put, as she failed to break the 14m barrier.
An assured performance of 23.49s in the 200m saw her claw back crucial points, however, and she ended the day with 4,057 points, 72 ahead of nearest rival Nafissatou Thiam of Belgium.
Ennis-Hill's teammate Katarina Johnson-Thompson closed out the session in fourth place thanks to impressive performances in the high jump (1.98m) and 200m (23.26s).
The heptathlon concludes on Saturday with the long jump, javelin throw and 800m.
Neil Wilkes
