American star Ryan Lochte kept up his phenomenal form at the world short course championships on Saturday when he set a world record 50.71sec in the men's 100m individual medley semi-finals.
On Friday, the five-time Olympic champion broke the 200m individual medley world record on his way to winning his fourth gold of the championships.
He was already under world record time by the end of the butterfly leg and he continued to eat into it over the following three laps.
Australia's Kenneth To recorded the second fastest time with 51.47 and George Bovell of Trinidad and Tobago was third with 51.66.
"I have the 200m backstroke final (before the 100m individual medley final) on Sunday so I knew if I wanted any shot at this record, it had to be tonight," said Lochte, who knocked .05sec off the old mark set by Slovenia's Peter Mankoc in 2009.
"I messed up in a couple of places tonight so I know there is some room for improvement."
In the women's 200m individual medley, China's Ye Shiwen attacked in the final 25m to win gold as she touched the wall in 2:04.64 to record a championship record and win her first world short course gold after having previously won three silver.
Katinka Hosszu of Hungary held on to win silver with 2:04.72 for her fourth medal of the championships, while Great Britain's Hannah Miley overcame a sluggish first 150m to win bronze with 2:07.12 to add to her 400m individual medley gold.
"I'm so happy I came in first today. It feels so good," said 16-year-old Ye, who stunned the sport at the Olympics when she captured gold in the 200m and 400m medleys.
"I competed against Hosszu many times in many events. This time she was stronger than ever. But I thought 'for sure I won't give up'. I had a chance to come back because in the breaststroke she is not so strong."
Ruta Meilutyte added the 100m breaststroke title to the 50m breaststroke gold that she won earlier in the week as she dominated the race to win with a new championship record of 1:03.52.
Meilutyte quickly took the lead and was under world record pace at the halfway mark and while the 15-year-old was unable to hold the pace in the second two laps, there was little chance of her letting the lead slip.
Alia Atkinson added the 100m breaststroke silver to the 50m breaststroke in 1:03.80, while Denmark's Rikke Moeller Pedersen came home for bronze in 1:04.05.
Robert Hurley finally ended Australia's wait for a gold medal with victory in the men's 50m backstroke.
Hurley touched the wall in 23.04 seconds to beat the USA's Matthew Grevers in 23.17, whose silver adds to his gold in the 100m backstroke, and Russia's Stanislav Donets who came home in 23.19 to win the bronze.
Nicholas Santos ended a similar wait with Brazil's first gold medal as he raced home in a championship record of 22.22 to win the men's 50m butterfly.
He had already broken it once in Istanbul and this time it was enough to hold off the challenge of 100m butterfly champion Chad Le Clos, who won silver with 22.26, and the 100m butterfly silver medallist Thomas Shields, who took bronze in 22.46.
There was a second gold for the USA's women's relay squad as their quartet of Megan Romano, Jessica Hardy, Lia Neal and Allison Schmitt won the 4x100m freestyle in 3:31.01.