Victory was earlier awarded to compatriot Hunter Armstrong after it was ruled that no part of Ress's body was above the water as he reached first for the wall.

Ress, who had set the pace in the heats and the semi-finals, was later reinstated as the winner and the medal ceremony held again, with Armstrong taking silver and Polish teenager Ksawery Masiuk having to settle for bronze.

Canadian Summer McIntosh continued her superb run in the Hungarian capital after the 15-year-old beat fellow teen Katie Grimes, of the United States, to collect the 400m individual medley title.

Gregorio Paltrinieri, gold medallist at the Rio Olympics, set a new championship record in the 1500m freestyle, comfortably finishing ahead of Robert Finke and Florian Wellbrock in a time of 14:32.80.

The Italian looked on course to break Sun Yang's world record of 14:31.02 but faded in the last 100 metres.

"So many people thought I was finished. I am not a person who lets himself be influenced by others but in these days I had enough doubts," Paltrinieri, 27, told reporters.

"Then I said 'no' and I felt stronger but I had to prove it in the race. I was in lane one, I felt the whole arena on me, but I didn't think so much. And time was not the priority today - today I dived in with the will to win."

Sweden's queen of the pool Sarah Sjostrom added the 50m freestyle crown to her remarkable list of victories as she claimed a 19th individual medal at the world championships, edging out Katarzyna Wasick and Meg Harris.

The 2012 Olympic champion Ruta Meilutyte clinched gold in the women's 50m breaststroke, beating Italian Benedetta Pilato by 0.10 seconds, with Lara van Niekerk of South Africa coming home in third.

It was a remarkable comeback for Lithuanian Meilutyte, who was handed a 24-month suspension in 2019 for anti-doping violations and returned to competitive action only in December last year.

Australian Associated Press