Germany's Niklas Kaul took advantage of the injury withdrawal of defending champion Kevin Mayer on Thursday to strike decathlon gold at the World Championships.

Kaul, in third place heading into the 1,500m, the last event of the gruelling 10-discipline test of athleticism, powered home to finish seven seconds clear and seal a winning total of 8,691 points.

Maicel Uibo of Estonia took silver with 8,604pts. Canada's Damian Warner claimed bronze with 8,529pts.
The complexion of the final had been altered dramatically earlier in the session when Mayer bowed out tearfully at the Khalifa Stadium.

Mayer's attempt to retain his title ended in the pole vault, the Frenchman exiting after two aborted jumps.
Mayer, who had taken the lead in the overall standings after the discus, fought back tears as he exited after pulling up on his second attempt.

The Frenchman had been limping noticeably after the opening discipline of the night, the 110m hurdles, with a heavily strapped left ankle.

However, he stormed back to register a strong performance in the discus, topping the round with his second throw of 48.34m.

That saw him take the overall lead with 6,310 points, but his inability to register a jump in the pole vault ended his challenge.

"I am not okay, but it will be fine," Mayer said afterwards. "It was disappointing because I was leading, but this is our sport."

Mayer revealed he had been troubled by a niggling injury to his right knee before suffering a hamstring injury on Thursday.

With Mayer out, the gold was suddenly up for grabs. 

Canada's Pierce LePage took the lead after the pole vault, with Uibo and Warner in the silver and bronze positions.

Kaul then moved into contention with a monster throw in the javelin of 79.05m to leave him just 19 points off the lead heading to the 1,500m, with Uibo in the gold medal position.

Kaul was in control throughout the 1,500m, moving into the lead with just under two laps to go and pulling away to bag 841pts for a winning margin of 87pts.