Katarina Johnson-Thompson will race for Olympic heptathlon gold in the 800m on Friday night after finishing the morning session in second place, 121 points behind Nafissatou Thiam.
Belgium’s Thiam tops the standings with 5,924 points, followed by the Briton with 5,803 and Switzerland’s Anna Kaelin on 5,694.
It means Johnson-Thompson will have to run roughly eight seconds quicker than the defending champion to win.
The world champion began the day with a 48-point lead but knew it would be tough with Thiam’s best event – the javelin – yet to come in Paris.
She registered 6.40m in the long jump, enough to keep her ahead of Thiam, who could only cut her lead by three points.
Johnson-Thompson then threw a season’s best 45.49m in the javelin – comparatively one of her weaker events – but it was not enough to stop Thiam replacing her at the top of the standings.
Thiam’s huge throw of 54.04m helped her take the lead from Johnson-Thompson and set up a thrilling finale.
The 800m takes place at 19:25 BST, with live coverage across BBC platforms.
How close to gold is Johnson-Thompson?
It will be a tough, tough ask for Johnson-Thompson under the lights – she will, ultimately, need the race of her life to claim gold.
There are just 103 points between Johnson-Thompson and Thiam’s personal bests in the 800m.
Johnson-Thompson’s best time is 2:05.63, while Thiam’s is 2:11.79.
That would earn Johnson-Thompson 1,064 points, and Thiam 961.
However, the Briton has given herself a chance, having produced some of her best performances over the past two days.
On Thursday, she registered a season’s best performance in the 100m hurdles, logged her best mark for five years in the high jump and finished with a career-best throw in the shot put to top the standings.
But Thiam was always going to respond on Friday in the events she has historically been stronger in.
The Belgian is the two-time defending Olympic champion and has won multiple world and European golds.