Kazan: Australia`s Cate and Bronte Campbell stormed into the 100m freestyle semi-finals on Thursday at the world swimming championships in their quest for more gold medals in Kazan.
Having helped Australia win the 4x100m freestyle relay last Sunday, the siblings opened their individual campaigns with fast times into the evening`s semi-finals.
Cate Campbell, the defending champion, matched Sweden`s Sarah Sjostrom, who broke the women`s 100m butterfly world record in taking gold on Monday, with the joint fastest time of 53.22 seconds.
Bronte Campbell was right behind at 0.28secs back, just ahead of Olympic champion Ranomi Kromowidjojo at 0.63sec.
"I executed a good race plan, I could see where everyone was in my heat so that`s a nice start," said Cate Campbell.
"It`s been a fantastic week so far and it`s all about keeping it going now."
Missy Franklin of the USA, who left the Barcelona championships two years ago with six golds but has only two bronzes to show so far, continued her disappointing Kazan campaign by finishing 10th fastest.
"We all know our priority is to get to the Olympics next year," said Franklin.
"Sometimes we get disappointed and so do our fans, but we`re doing the best we can."
Australia`s Mitchell Larkin, who won the 100m world title on Tuesday, posted the fastest time in the 200m backstroke heats of one minute, 55.88 seconds into the evening`s semi-finals as he bids to do the double.
After his 100m gold, Larkin said he had deliberately kept the celebration of his first world title low-key with an eye on the 200m.
"I came here with a job to do in the 100, 200, 50m and the relay so I was happy to forget that gold and then really focus on the process and getting though the rounds," he said.
Japan`s silver medallist Ryosuke Irie was second fastest at 0.80secs behind and there will be a new champion as Ryan Lochte, the 2013 winner, is sitting out the event.
There was a huge surprise in the women`s 200m breaststroke heats as Russia`s defending champion Yuliya Efimova failed to reach the semi-finals as one of the 16 qualifiers.
Efimova won the women`s 100m breaststroke on Tuesday having only finished serving a 16-month ban in March after traces of a steroid were found in her system.
She finished 2.82 secs slower than Japan`s Kanako Watanabe, the fastest through to the evening`s semi-final.
Britain`s Adam Peaty, who has been the outstanding male swimmer in Kazan after completing the 50 and 100m breaststroke double, struggled in the morning`s 200m heats.
The 20-year-old has three gold medals and two world records after helping Britain win the mixed medley relay title on Wednesday, but admitted the last few days had taken their toll.
With the top 16 advancing to the evening`s semi-finals, Peaty was 26th at 4.12secs behind Germany`s Marco Koch, the fastest through in 2:09.12 mins.
"I wanted to go a little bit faster but I think these last few days have taken so much out of me, emotionally and physically," said Peaty.
"I`m very, very tired, but I`ve got a relay job on Sunday, so one more 100.
"I`m really disappointed in that time but I don`t want to get too emotionally involved, and step up for the relay."
South Africa`s Olympic 100m champion Cameron van der Burgh, who won silvers over 50 and 100m here, also failed to advance at 21st fastest and 3.25secs behind Koch`s time.
"I`ve been giving it so much over the last couple days and there was just nothing left in the tank at the end," said the 27-year-old.
There were no surprises in the 4x200m freestyle relay heats as Italy, the United States, Australia, Sweden, China, Great Britain and France all went through to the evening`s final.
There was drama in the mixed zone as Zambia breaststroker Tilka Paljk was carried through on a stretcher, suffering from hyperventilation, having finished 46th fastest in the 200m heats, but the 18-year-old later recovered.