DOHA: Defending champion Ahmed Hafnaoui failed to advance from the 800 metres freestyle preliminaries at the World Championships in Doha on Tuesday in another setback after his 400m blow out. The Tunisian was only 18th fastest in the 800 heats, with his time of seven minutes, 51.52 seconds more than 14 seconds off his championship-winning swim at Fukuoka last July. Olympic champion Hafnaoui was favourite for the 400 title but crashed out as the 17th-ranked swimmer in the heats on Sunday. The 21-year-old had been less than bullish about his chances of setting fast times at Doha when he faced reporters on the eve of the meet but his results raise more questions about his preparations for the Paris Olympics. Hafnaoui, who is still to defend his 1,500m freestyle title, raced for Indiana University last autumn but ended up training with The Swim Team in Orange County, California, under former U.S. national team coach Mark Schubert. He recently returned to Tunisia, though, and told reporters he was hoping to have a visa issue resolved to train in the United States. Hafnaoui’s elimination in the 800 means none of the medallists from Fukuoka will feature in the final. Italy’s Luca De Tullio topped qualifying with a time of 7:46.52 ahead of Irishman Daniel Wiffen, who broke the 800 short course world record at European championships in December. In the women’s 200m freestyle heats, China’s Li Bingjie was fastest for the semi-finals ahead of New Zealander Erika Fairweather. Fairweather won the 400m freestyle world title ahead of Li on Sunday. Hong Kong’s Siobhan Haughey, the Tokyo Olympics silver medallist, eased into the semis fourth fastest. Estonian surprise package Kregor Zirk emerged fastest in the men’s 200m butterfly heats, with Fukuoka runner-up Krzysztof Chmielewski of Poland finishing fifth quickest to reach the semi-finals. Japan’s Tomoru Honda, who won silver at his home Tokyo Olympics and bronze last year in Fukuoka, also eased through ranked ninth. Men’s 100m breaststroke world champion Nic Fink was joint top qualifier for the non-Olympic 50m semis along with Belarusian Ilya Shymanovich, who is swimming as a neutral athlete due to World Aquatics restrictions on Russian and Belarusians at the meet. World record holder Adam Peaty, who took bronze in the 100m breaststroke on Monday, qualified 12th for the 50m semis.