Kazan: Katie Ledecky claimed her third world championships gold on Wednesday to leave her poised to make history while Adam Peaty`s breaststroke double capped an outstanding night for Britain in Kazan.
Ledecky underlined her status as the stand-out performer in the Kazan pool by claiming victory in the 200m freestyle final just 24 hours after breaking the world record for the second time in winning the 1500m freestyle final.
The USA`s triple world record-holder had already won the 400m gold last Sunday and she can become the first women to win four freestyle world titles when the 800m heats start on Friday with the final on Sunday.
"I have trained a lot to be able to do these races and I knew I could trust my training and this confidence has filled my swims this week," said the 18-year-old, who won the 200m freestyle final in 1min 55.16sec.
"I have a couple of races left to give my all in.
"I have been preparing all year for the whole year for these world championships."
Fresh from setting the world 50m breaststroke record of 26.42secs in Tuesday`s semi-final, Britain`s Peaty added to his 100m world title with victory over the sprint distance on Wednesday.
The 20-year-old won the 50m final by clocking 26.51 in the final with South Africa`s Cameron van der Burgh, the 2013 world champion, taking silver, at 0.15sec back.
The Briton has matched David Wilkie`s breaststroke 40-year-old double when the Scot won the 100 and 200m golds at the 1975 world championships.Peaty then backed up his individual win by helping the British team win the 4x100m mixed medley event in a new world record time.
It was the third time the event`s record had fallen on Wednesday alone after Russia, then the USA broke it in the morning`s heats and it means world records have now fallen on ten occasions in Kazan.
With two gold and two world records from his worlds debut here, Peaty can still claim a third individual title when the 200m breaststroke heats begin Thursday.
"It`s my first world championships, so I never thought I`d walk away with three gold medals, but I fought for every centimetre and every inch," said Peaty.
"All my training was for the 50m final tonight and then the 100m in the relay.
"It`s been the stuff dreams are made of, but head down now for the 200m heats in the morning."
Chinese long-distance expert Sun Yang claimed his second gold with victory in the 800m freestyle final, but he was made to work to retain his title after Italy`s Gregorio Paltrinieri pushed him all the way.
Sun clocked seven minutes, 39.96secs, but Paltrinieri swam a new European record at 0.85secs back as Australia`s Mack Horton took bronze at 4.06.
Defending Olympic and world champion Chad le Clos had to settle for silver in the men`s 200m butterfly final as Hungary`s Laszlo Cseh beat him on the wall to capture his first major title for a decade.
Cseh clocked 1min 53.48sec to beat Le Clos by just 0.20sec.
Ryan Lochte of the USA is on course to win his fourth consecutive world 200m individual medley gold as the quickest into Thursday`s final in 1:56.81.
Australia`s Cameron McEvoy is also the name to beat in the men`s 100m freestyle final, also on Thursday, having been the only qualifier from the semi-finals to go under the 48 seconds mark.
"There is a lot of excitement around the 100m freestyle," said McEvoy.
"It`s just a matter of recovering as much as I can before then and I`ll be using the same race plan regardless of who is in the final."
Russia`s Vladimir Morozov, who had posted the world`s joint fastest time this year coming into Kazan, was disqualified in his semi-final after leaving his blocks too early.
Olympic champion Nathan Adrian of the United States was fifth fastest.
Fresh from winning the women`s 100m world title on Tuesday, Australia`s Emily Seebohm was fifth fastest into Thursday`s 50m final as China`s Fe Yuanhai clocked the quickest time of 27.18secs.
Japan`s Natsumi Hoshi was the fastest into the women`s 200m butterfly final on Thursday at 2:06.36 secs, but the big surprise was Hungary`s `Iron Lady`, Katinka Hosszu failing to qualify as 13th fastest in the semi-finals as the 200m IM champion missed out.