By Drew Farmer for Bahamas Athletics

South Africa's Wayde van Niekerk won his second world title in the 400m as he blew away the rest of the pack in the final straight away in Tuesday night's men's 400m finale.

Van Niekerk showed some signs of fatigue as he tallied a 43.98 first place finish. The South African still has the 200m semifinal and final to run and with the 400m gold now in his possession, a gold medal 200/400 double is on the cards in London.

The final wasn't without a major controversy as Botswana's Isaac Makwala was locked out of the London Olympic Stadium ahead of the race final. Reportedly, Makwala had been suffering from a stomach flu and was withdrawn from the race by the IAAF.

Despite being taken out of the race, Makwala arrived claiming to be "fit and ready."

According to the BBC, the IAAF had said Makwala was too ill to race, although the Botswana team claimed there was no clarity to the reports given by the athletics organization. The IAAF's Head of Medical Services, Pam Venning, appeared on the BBC's live coverage following the race and did little to clarify the situation. Venning even made the decision seem more bizarre when grilled by the channel's announcers.

Van Niekerk has dominated the 400m race over the last three years. Since winning gold at the World Championships in Beijing in 2015, the South African has run to gold in three straight competitions.

This year's World Championships have been the last edition to feature athletics' greats Usain Bolt and Mo Farah. At only 25, Van Niekerk is in the prime of his running career. The runner could fill the void left by both Bolt and Farah as the sport's top star and a double at this year's World Championships could increase his reputation as the new world's best on the track.

Makwala's lane seven was left empty for the race and the Botswanan would have pushed Van Niekerk to the finish line. Without the disqualified runner able to compete, the silver medal went to the Bahamas' Steven Gardiner while bronze went to Qatar's Abdalelah Haroun.

Gardiner's silver medal is his best finish at a major event and his first medal in the men's 400m. At last year's Olympics in Rio, the 21-year-old won bronze in the 4x400m relay. Haroun was the surprise of the final and that may have been down to the exclusion of Makwala. The Senegalese-born Qatari national stormed home just behind Gardiner to grab bronze.

Following the race, Van Niekerk spoke about the race.

"It is amazing to win the world title," Van Niekerk said. "It is a blessing. I hope the fans enjoyed that.

"I'm used to the lactic [acid in legs] but I need a few minutes to recover from that effort and I'll be fine.

"I've got a good team who will help me recover well for the 200m and I'm looking forward to that."

Van Niekerk now has the men's 200m semifinals to run on Wednesday night with the final to follow on Thursday.