Athletics greats Caster Semenya and Allyson Felix lit up the track on the final day of the world championships - but Usain Bolt stole the show in front of his adoring fans.

South African star Semenya added a third 800m crown to her tally to put her alongside another African great, Maria Mutola, as the only women to have won the title three times.   

Semenya hinted that it would now be time to tackle the world record of 1:53.28 set by Jarmila Kratochvilova in 1983.

"We need to clear 1:55 first and it will require a lot of hard training. I have Olympic, world and Commonwealth titles now so maybe it is time to target the world record," said Semenya, whose last defeat in the event dates back to 2015.

Later Felix ran a stunning leg in 48.7 seconds in the women's 4x400 metres relay to set the United States up for an easy victory and take her record world medals tally to 16, two ahead of retired Jamaican duo Merlene Ottey and Bolt.

Retiring superstar Bolt put on one last appearance, the 100m and 200m world record-holder accorded a lap of honour in front of the 60,000 spectators who stayed on after the finals were over.

"It's been a rough couple of days, and this is a very emotional moment for me," said the 30-year-old Jamaican referring to his dramatic collapsing to the track with cramp in the anchor leg of the 4x100m relay final 24 hours earlier.

"I always tried my best and gave 100 percent all the time and above all put on a good show."

Bolt then went on a lap of honour to the tune of "Reggae Nights" raising his arms and applauding the crowd, embracing his parents on the track and then finishing with a final flourish of his trademark 'lightning bolt'.

USA denied in the relay

Trinidad and Tobago denied United States a seventh successive world 4x400 metres relay title when Lalonde Gordon overhauled Fred Kerley on the final straight to win a breathtaking final.

The US led for most of the race and appeared to be on course for another win after Michael Cherry ran a strong third lap to extend their lead before handing the baton to Kerley.

But Gordon gave chase and ran a superb final lap for the Caribbean islands, catching the American on the home straight to give Trinidad their first world title in this event and add to the list of upsets at the championships.

Manangoi leads Kenya one-two

Asbel Kiprop failed in his bid for a fourth consecutive 1,500 metres gold medal at the world championships - but Kenya still celebrated a dazzling one-two with new champion Elijah Manangoi leading home his friend Timothy Cheruiyot.

Manangoi, the fastest man in the world this year, sped past his young training partner on the home straight of the last individual track event to take the title in 3 minutes 33.61 seconds, just ahead of Cheruiyot (3:33.99).

Kiprop, who had briefly threatened to make it a Kenyan clean sweep, found the pace too hot on the last lap, fading into ninth place in 3:37.24.

Ayana stunned

Kenyan Hellen Obiri produced an astonishing last lap to leave defending champion Almaz Ayana in her wake as she won the women's 5,000 metres and claimed her first major title on Sunday.

Ethiopia's Ayana, who led Obiri for more than half the race, was denied a double after winning the 10,000 metres with a devastating run earlier at the championships.

The pair broke clear of the pack after one third of the race and opened up a huge gap as they set a blistering pace.

Ayana led with Obiri on her shoulder into the final lap until the Kenyan, silver medallist in Rio de Janeiro last year, burst past with 300 metres left and stormed home to win in 14:34.86, more than five seconds clear of her rival.

Croatia and Qatar win field golds

Double Olympic champion Sandra Perkovic eased her way to a second world discus title after being the only athlete to throw over 70 metres.

The Croatian, who first won the world title in 2013, threw 70.31 on her second attempt which was enough to triumph in the same stadium in which she won Olympic gold in 2012.

Qatar's Mutaz Essa Barshim secured the global high jump title his talent has promised for so long when he completed a faultless series, culminating in a winning leap of 2.35 metres.

The Qatari, whose 2.43m best is the second-highest in history after Cuban Javier Sotomayor's 2.45 set 24 years ago, has won silver and bronze at the last two Olympics and silver in the 2013 World Championships.