Kenya's Olympic champion Emmanuel Wanyonyi added the world crown to his collection with a hard-fought victory in the men's 800 metres on Saturday.

Wanyonyi timed a championship record of 1min 41.86sec for gold in Tokyo, just four hundredths of a second ahead of Algeria's fast-finishing Djamel Sedjati.

Defending champion Marco Arop of Canada had to settle for bronze in 1:41.95 in a reshuffle of the podium places with Sedjati from last year's Paris Olympics.

"I really wanted to have a good race, a fast one but the time was not important for me. The gold medal was," said Wanyonyi, who is now aiming for victory again when the next world championships take place in Beijing in 2027.

"I wanted to do everything to secure the gold. I expected the race to be really competitive and very fast but I wanted to make sure to just win this gold," he said.

"Now I need to defend this title. I want to be a double world champion. Maybe I will start to think about the world record too."

Wanyonyi, one of 12 children who left school aged 10 to help herd his family's cattle, said though that Olympic gold in Los Angeles in 2028 remained "the biggest goal".

The 21-year-old is a master of gun-to-tape tactics and he duly raced straight into the lead at the start.

"Today's race was fast and hard," Wanyonyi said. "I wanted to run a fast race, that's why I went to the lead. I wanted to run my personal best here and I am happy to walk away with the championship record."

He and Arop briefly bumped shoulders before the Kenyan moved away, clocking a rapid 49.27sec through the opening 400 metres.

Wanyonyi failed to drop the chasing pack down the far straight, however, and coming off the bend, the packed crowd at Tokyo's National Stadium rose to their feet.

- Tactical race -

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(From L) Algeria's Djamel Sedjati, Canada's Marco Arop, Kenya's Emmanuel Wanyonyi and Spain's Mohamed Attaoui / © AFP

Arop made his move alongside Wanyonyi.

And then from a distant sixth place came Sedjati, who strained every sinew to pull up with the leading pair before Wanyonyi responded with a final, decisive kick to ensure victory by the closest of margins.

"It was a very tactical race," said Sedjati. "Everything happened in the way I planned, except the gold medal.

"But I'm very happy and satisfied with this silver. I was very worried about my father. I had him on the phone yesterday and he told me that he was so stressed, and that stressed me.

"I thought about him during the race, but now I can tell him that everything is OK."

Ireland's Cian McPhillips, the first Irish athlete to run a 800m final at a world championships, was fourth in 1:42.15 as all eight athletes posted sub-1:43 times in a high-quality race.

Never in doubt, however, was David Rudisha's world record set by the Kenyan at the 2012 London Olympics.

The double Olympic champion, also twice a gold medallist at world championships, is a friend of Wanyonyi and was an interested spectator in the stadium.

The 36-year-old was sat alongside World Athletics president Sebastian Coe, himself a two-time Olympic silver medallist over the two-lap race and whose best of 1:41.73 still puts him joint eighth on the all-time list.

"I met David Rudisha yesterday," Wanyonyi said. "He told me just to take a rest and focus, and everything is possible."