Kevin Mayer's defence of his world decathlon title lasted just two events on Friday in Budapest as the left Achilles problem that had been niggling him proved too much.
The morning session allowed the spotlight to fall on the decathletes and field events specialists as the track stars had a rest.
They will return to the limelight later Friday when Noah Lyles and Sha'Carri Richardson bid to add 200m gold to their 100m crowns.
Friday's early action proved a fiesta for Indian male javelin throwers, all three of them, headed by Olympic champion Neeraj Chopra, reaching Sunday's final.
Two Ukrainians, Yaroslava Mahuchikh and Iryna Geraschenko, will bid to bring some joy to their compatriots back home in Sunday's high jump final after qualifying on Friday.
The writing had been on the wall for two-time world champion Mayer from the start as his 100m time of 10.79sec was well off his best.
The long jump confirmed his problems as a leap of 7.25m -- some way off his personal best of 7.80m -- left him shaking his head ruefully.
Trailing in 16th place and over 200 points adrift of Olympic champion David Warner, Mayer called it a day and will hope for better things in front of his home fans at the Paris Olympics next year.
"There is frustration but also I am at peace with myself," said Mayer, who had been undergoing eight hours of physiotherapy on a daily basis since he first realised he had the problem a fortnight ago.
"I gave everything and now I can go on holiday with a free mind. My body is telling me I need to rest before the Olympic Games," added the 31-year-old.
- 'Calm and cool head' -
As he bowed out the battle to take his world crown heated up.
However, it was not Warner who led after three events but surprise package Leo Neugebauer from Germany.
The 23-year-old treated the sparse crowd to two celebratory fist-pumping displays after recording personal bests in both the long jump and the shot put.
The latter saw him soar past Warner in the overall standings, turning a 28-point deficit into a 96-point lead -- 2,908 to 2,812 -- heading into Friday evening's two events.
In the javelin, Chopra sailed into the final posting a season's best mark of 88.77m, over six metres further than the second best throw of his group, Germany's Julian Weber.
Chopra's teammate DP Manu had the third best throw of the group with 81.31m and also progressed.
Kishore Jena joined them after posting a mark of 80.55m in his group.
Chopra, 25, said he had sensed he was in top form when he arrived at the stadium.
"I was able to save energy for the final since I threw with only 90 percent effort," he said.
"I will definitely give everything in the final as I would like to have a world gold as well.
"I hope we make our country proud again. Of course, the pressure is higher on me but I like these challenges."
Chopra could be set for a cracking duel with Pakistan's Commonwealth Games champion Arshad Nadeem, who topped Jena's qualifying group with 86.79m.
Ukraine have had little joy thus far but the high jump offers hope of a golden ending to the championships.
Mahuchikh seeking to win gold after two world silvers eased into the final, jumping 1.92m.
Her teammate Iryna Geraschenko also made the final, squeezing in with a best jump of 1.89m, leaving the Olympic finalist deflated at her performance but prepared to up her game for the final.
"Psychology is a huge part of our event," said Geraschenko.
"I will be much stronger in the final, jumping with a calm and cool head.
"It should be a great final and I would like to be part of the battle."
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