South Africa sprint star Wayde van Niekerk stormed to 400 metres gold at the World Championship but admitted he was disappointed to be controversially denied a showdown with Isaac Makwala.
The 25-year-old defended his title in 43.98 seconds, finishing ahead of Steven Gardiner and Abdalelah Haroun, in London on Tuesday.
But he did not face Botswana's Makwala - a leading challenger - after he was denied entry to the London Stadium despite insisting he was fit after an outbreak of the norovirus bug.
The 30-year-old, who was also pulled out of the 200m heats on Monday, was withdrawn by organisers the IAAF "due to a medical condition" while Botswana insisted they were given no reason for Makwala being denied entry.
"It depends whose fault it was," said Van Niekerk when asked what he would have done. "There's a lot of fingers being pointed, I just know he's ill and in a different hotel than I'm in.
"I would have loved him to have the opportunity. He was in great form, I believe he would have done very well. I have so much sympathy for him.
"I wish I could give him my medal but it's sport and these things happen.
"It could have been any one of us. It's a journey and life, we all have tough times and we have to get back up and fight harder.
"It was a definitely a heartbreaking moment. I saw him just before the 200m heat and the only thing I could think of was wrapping my arms around him and telling him to get well soon."
43.98 earns @WaydeDreamer gold 🥇 in the 400m pic.twitter.com/KnZAxMintB
— IAAF World Champs (@IAAFWorldChamps) August 8, 2017
Without Makwala, Van Niekerk was never challenged, with Gardiner of the Bahamas almost half a second behind in 44.41 secs and Haroun third in 44.48s.
Van Niekerk was so comfortable he even slowed down as he approached the line as he added to his Olympic title from Rio and will now target the 200m.
He added: "I knew it was going to be a quality race. At the same time it was freezing. I struggled to get myself warmed up and for about 200m I was doubting my momentum. The last 150m I put in an extra gear.
"I looked up the the screen and saw I was ahead, thought about my health and thought if the time wasn't going to come then there was no point pushing myself to the limit."
Meanwhile, Pierre-Ambroise Bosse took gold in the men's 800m in one minute 44.67 seconds, ahead of Poland's Adam Kszczot and Kipyegon Bett in third.
The Czech Republic's Barbora Spotakova also took the javelin title ahead of Lingwei Li after throwing 66.76m to regain the crown 10 years after first winning it in Osaka.
The double Olympic champion, who won at London 2012, said: "At this stadium, I am unbeatable. There must be something in the air about London.
"I cannot explain it but when I enter this stadium, I always feel so calm and relaxed. I believed I could really win it today, I was so focused and confident.
"The whole day I was thinking about my last world title which was 10 years ago in Osaka. Actually, it is also almost exactly five years since my Olympic title here in London."
Conseslus Kipruto also claimed the 3,000m steeplechase crown ahead of Soufiane Elbakkali and the United States' Evan Jager.
Kenya's Kipruto clocked eight minutes 14.12 seconds with Elbakkali less than half a second behind.
American Sam Kendricks took gold in the pole vault with a height of 5.95m, ahead of Poland's Piotr Lisek and France's Renaud Lavillenie.
Elsewhere, Holland's Dafne Schippers and the Ivory Coast's Marie-Josee Ta Lou, who took 100m bronze and silver respectively on Sunday, cruised through to the semi-final of the 200m.
Schippers said: "I felt really good. It was an easy race so glad to get it done."
The event was missing the USA's Tori Bowie, who was still recovering from the fall she suffered while winning the 100m on Sunday.
In the women's shot put, Lijiao Gong of China topped qualification for the final with 18.97m with the USA's Michelle Carter five centimetres behind her.
