KAZAN, Russia (REUTERS) - Hungary's Katinka Hosszu was the outstanding performer in the women's 400 metres individual medley heats, as the final morning session at the world championships concluded at the Kazan Arena.
Chasing her third world title in the event since 2009, she recorded 4min 32.78sec to easily qualify fastest for the final later on Sunday as she looks to add to her 200m IM title.
Barbora Zavadova, of the Czech Republic, qualified second quickest, 2.82sec behind, with Canada's Emily Overholt in third.
However, Olympic champion Ye Shiwen, who also holds the world record at 4:28.43, failed to advance. The Chinese, who finished eighth in the 200m IM final, could only finish in 15th place, a disappointing 10.18sec behind Hosszu.
"World records are something we always look at and I have been chasing them all the time," said Hosszu. "It is the ultimate goal and let's see how much faster I can go tonight. Hopefully I will be faster than I was this season.
"It's going to be really tough later and there have been swimmers who have been waiting for this day but I think I will be focused and ready to go."
In the men's 400 IM, Chase Kalisz, of the United States, posted the fastest time of 4:11.83, ahead of European champion David Verraszto, of Hungary. Japan's current world champion Daiya Seto was third.
"I will have a crucial race of this championship tonight," said Seto. "I have to do my best to fight for the medals and to confirm my title as world champion in this distance."
The men's 4x100m medley relay saw the United States take bragging rights into the final as fastest qualifier. The US quartet, looking to regain the title from France, posted 3:31.06, with the defending champions in third while Australia are sandwiched in between them.
Singapore's Quah Zheng Wen, Lionel Khoo, Joseph Schooling and Danny Yeo clocked 3:40.93 to finish 19th among 27 teams.
Schooling clocked a slow 52.79 for his butterfly leg, clearly fatigued after his superb 50.96 the previous night in his bronze-winning swim in the 100m fly.
In the women's 4x100m, China topped qualifying with 3:57.04. The United States finished second, with Missy Franklin set to return for the final.
Singapore's Quah Ting Wen, Samantha Yeo, Nur Marina Chan and Amanda Lim were 23rd out of 25 teams in 4:17.26.
The championships will close later on Sunday with Sun Yang of China attempting to win his third world title of the week in the men's 1,500m freestyle. He has already won gold in the 400m and 800m freestyle.
Sun will face in-form Gregorio Paltrinieri, of Italy, who finished over four seconds ahead of the Chinese in qualifying. Paltrinieri revealed that the pair had talked together following the Italian's heat win.
"He (Sun) thinks I can do very well in the 1,500," he told reporters. "So I think he's a bit afraid of me. I've got the pace."
Russia's controversial star Yuliya Efimova, returning from a doping ban, and Lithuania's Ruta Meilutyte will also go head-to-head in the women's 50m breaststroke final.