Jessica Ennis-Hill leads the women’s heptathlon after the first day of competition, but with just 100 points separating her and fellow Brit Katarina Johnson-Thompson in fourth, day two looks to be set for fierce competition.
Ennis-Hill produced a solid shot putt display, reaching 13.86m, but it was this event that saw Johnson-Thompson fall from first to sixth overall, with her best throw over two metres down on Ennis-Hill.
But the 23-year-old from Liverpool bounced back in the fourth and final event of the day, winning her heat of the 200m ahead of Ennis-Hill in a time of 23.26 to move back up to fourth place.
Just 72 points separate Ennis-Hill from Belgium’s Nafissatou Thiam and the London 2012 champion knows to expect some strong challenges on day two.
“It’s always nice to be leading after the first day,” Ennis-Hill said. “Those girls have big jumps in the long jump and can all run good 800 metres. It’ll be a challenging day, and another long one. I want to go and put all the pieces together, rest up and come back tomorrow stronger.”
Elsewhere, Greg Rutherford overcame two fouls in qualifying to reach Saturday’s long jump final, where he will defend his title from London 2012.
The Milton Keynes athlete produced a jump of 7.90 with his third and final effort of the evening, enough to see him progress in seventh place.
“Going into [Saturday], it is a completely new competition. It doesn’t matter what happened today,” Rutherford said.
“A few people might say Greg is not on form but it is up to me to go out there tomorrow and put it to rights.”
There were mixed fortunes for Martyn Rooney and Matthew Hudson-Smith in the men’s 400m heats, with three-time Olympian Rooney failing to qualify while his younger compatriot progresses to the semi-finals.
Rooney’s time of 45.60 saw him sitting in the second of three ‘fastest loser’ spots ahead of the final heat, but a quick race saw the 29-year-old drop out.
Hudson-Smith finished third to defending champion Kirani James, which guaranteed him a place in the next round.
Desiree Henry got her Olympic career off to a flying start, winning heat one of the women’s 100m heats, Asha Philip and Daryll Neita finished third and fourth respectively in their races.
And Sophie Hitchon qualified for the women's hammer final with a throw of 70.37m.