The reigning champion opened her heptathlon campaign, while Anna Hall took an early lead and Kate O’Connor impressed.

Day one of the women’s heptathlon in Tokyo packed four events into a single evening session, testing the athletes’ endurance and focus right from the start.

The competition opened with the 100m hurdles, where Great Britain's Jade O’Dowda won her race in a new personal best of 13.34 seconds, beating her previous best of 13.37. She crossed the line smiling and immediately high-fived compatriot Katarina Johnson-Thompson, who finished just behind her in second place with a season’s best of 13.44.

Ireland’s Kate O’Connor, European Indoor bronze medallist in the pentathlon, was also in the mix, finishing third with a personal best of 13.44. Olympic champion Nafi Thiam struggled to keep pace, finishing fifth with a season’s best of 13.61 amid recent disagreements with her Belgian team.

In the final hurdles heat, Americans Taliyah Brooks and Anna Hall impressed, with Brooks posting the fastest time of the entire field at 12.93, and Hall clocking a season’s best of 13.05. Great Britain’s Abigail Pawlett was having a strong race until she tripped on the last hurdle, rolling over the line, stopping the clock at 14.70.

The high jump proved challenging as the competition progressed. Brooks, who had been leading after the hurdles, couldn’t clear 1.80m and settled for 1.77m, visibly frustrated. O’Dowda cleared 1.80m but failed to pass 1.83m.

The bar then rose to 1.86m, a height that proved tricky for many athletes. O’Connor cleared it on her final attempt, setting another personal best and sparking a reaction in the field. Hall and Sofie Dokter had already cleared it, and Thiam managed to do so on her third try. Johnson-Thompson followed, also clearing 1.86m on her final attempt, marking a season’s best.

The next height, 1.89m, was too much for everyone except Hall and Thiam, who both cleared successfully, ending the high jump portion and shifting the overall standings. Hall moved into first place with 2210 points, Thiam was second with 2127, and Johnson-Thompson and O’Connor were tied in third on 2113 points.

In the shot put, Hall continued her strong showing with a personal best throw of 15.80m, further solidifying her lead. Thiam threw 14.85m, keeping second place. Johnson-Thompson threw a season’s best 13.37m, while O’Dowda recorded 13.55m.

Going into the 200m, Hall was still in front and extended her lead by running 23.50 seconds, just one hundredth of a second ahead of Johnson-Thompson’s 23.51. However, the fastest 200m time came from Pawlett, who bounced back from her earlier fall to run 23.25.

Thiam’s 200m time of 25.52 caused her to drop down the standings, allowing both O’Connor and Johnson-Thompson to climb higher on the leaderboard.

At the end of the evening, with four demanding events completed in one session, Hall leads the heptathlon with 4154 points. O’Connor sits second with 3906, and Johnson-Thompson is close behind in third with 3893.

Johnson-Thompsons said: "The timetable was really, really hard this time around. I remember looking at it before Paris last year and I was like, ‘not my problem’. And now that I'm doing it, yeah, it's tough, and it's going to get tougher as well with the long jump in tomorrow morning’s session. So this is the first time I've had the chance to catch my breath.

"It's the same for everyone. But yeah, I'm feeling it today. We haven't even had the chance to have a natter which we normally do. Everyone's just been on to the next, on to next. So yeah, I’ll see Jade and Abi, see how they're feeling.

"Today was solid, not great, not disastrous. We're in a good position, so let's see what tomorrow brings."

Brits Pawlett and O’Dowda are in 14th and 15th place respectively, with 3698 and 3696 points.

Day two of the heptathlon will resume on Saturday with the long jump, javelin and 800m to decide the final standings.