Canada's Olympic champion Damian Warner got his sixth attempt to win the world decathlon title off to his traditionally strong start on Saturday as he built a solid early lead after the opening three events.
Schedule | Results | Medals | TV Guide | Watch on DStv
Until last year, Warner had spent more than a decade putting his body through the torture of the 10-discipline event, regularly making the podium but never quite getting to the top step.
That changed in Tokyo when he won Olympic gold and he followed up this year with the indoor world title.
At the outdoor World Championships he has a record of 18th, third, second, fifth and third and although he is in the form of his life, at 32 he knows there will not be that many more opportunities to win it.
He opened up well with a 10.27 seconds 100 metres - slightly below his seasonal best but still well clear of anyone else in the field - to be up and running with 1030 points.
His long jump of 7.87 was also the best of the day by 17 cm and a season's best 14.99 metre shot put, though down on some of the bigger men in the field, was enough to keep him 90 points clear on 2846 points.
American Zach Ziemek, Puerto Rico's Ayden Owens-Delerme, Canadian Pierce LePage and world record holder Kevin Mayer of France were leading the chase, but German defending champion Niklas Kaul struggled all morning and was sitting 20th.
The competition picks up later on Saturday with the high jump followed by the 400 metres, with the concluding five events on Sunday - the last day of the championships.