South Korean teenager Park Tae-hwan became the first Asian to break the 15-minute barrier in the 1500m freestyle on the way to winning his third gold medal of the Asian Games on Thursday.
The 17-year-old broke clear of the field at the 1,000m mark and powered down the final 100m to touch home eight seconds ahead of his nearest rival in an Asian record of 14:55.03.
The double Pan Pacific champion has also claimed the 200m and 400m freestyle events in Doha.
Qi Hui also completed a hat-trick of gold medals for the under-pressure Chinese swimming team with a convincing win in the women's 200m individual medley.
The world short course champion clocked a time of 2:11.92, the third fastest in the world this year, to add to her 200m breaststroke and 400m Individual medley titles.
She used a strong breaststroke leg to pull away from the field and leave Japanese pair Asami Kitagawa (2:14.51) and Maiko Fujino (2:15.21) almost three seconds adrift.
STILL YOUNG
Qi put her impressive performance in Doha down to experience, and said she would decide early next year whether to focus her efforts on the breaststroke or individual medley ahead of Beijing.
''My experience helped me, it's my third Games,'' she said.
''Those of us who didn't perform here are still young. I'm pleased with my performance. I won in times close to my best.'' Japan's Kosuke Kitajima celebrated his return from injury with his second gold medal of the competition, successfully defending his 200m breaststroke title.
The double Olympic champion used his long glide and powerful strokes to power away, turning first at every wall to finish in 2:12.05.
Compatriot Daisuke Kimura picked up the silver medal for a second successive Games in 2:13.17, with 50m gold medallist Vladislav Polyakov of Kazakhstan third (2:13.60).
Japan won the first gold medal of the night in a tight men's 50m backstroke final, with Junya Koga (25.40) getting the touch over Asian record holder Ouyang Kunpeng of China (25.47) and South Korean Sung Min (25.57).
An ecstatic Tao Li won Singapore's second gold medal of the Asian Games with victory in the women's 50m butterfly, getting the touch in 26.73 ahead of China's Xu Yanwei and Japan's Yuka Kato.
Japan's two golds leaves them trailing China 16-14 in the swimming gold medals tally midway through the final night's racing in Doha.
China took 21 to Japan's 10 golds at the 2002 Asian Games in Busan.
