(CNN) -- Ryan Lochte doubled his gold-medal haul on the final day of the 10th FINA world short-course swimming championships in Dubai on Sunday.
The American added gold in the men's 200 meter backstroke -- setting a new championship-best time -- and the men's 100m individual medley.
The 26-year-old, the leading U.S. swimmer in the absence of his main rival Michael Phelps, also claimed a team gold as the U.S. won the 4x100m medley relay event, taking his title tally to six in Dubai.
Sunday's results took his overall medal total in all short-course world championships (which are held in 25m pools) to 21 -- four more than the previous record of 17 held by Sweden's Therese Alshammar.
Lochte's tally of seven medals at the 2010 championships is also a record, as he also picked up a silver in the 4x200m free relay.
"I knew before the meet that my last day would be one of the toughest, but I am always up for the challenge. This is probably one of the worst shapes I have been in for a world championships," he told the sport's official website.
"I'm not really 100%. I've done a lot of training, I haven't really rested for this meet and it's actually very good for me because it makes me want to race harder and it's a stepping stone for the  Shanghai worlds."
The United States led the final medals table with 25, which included 12 golds. Russia finished second on 10 (four golds), Spain claimed third place with eight (four golds), while China finished fourth with 14 medals (three golds).
Brazil's Cesar Cielo Filho completed a double in the freestyle sprint events, taking gold in the men's 100m ahead of French swimmer Fabien Gilot and Russia's Nikita Lobintsev to follow up his victory in the 50m.
Felipe Silva gave Brazil a third gold of the week when he won the 50m breaststroke in a championships-record time of 25.95 seconds.
In the women's events, Rebecca Soni secured a clean sweep in the breaststroke after adding the 200 meters title to the 50 and 100 meter she won earlier in the week. All her victories came in championship record times.
But it was Mireia Belmonte Garcia who was crowned the most successful female swimmer at the championships with four medals.
The 20-year-old Spaniard claimed three gold medals (200 meter butterfly, 200 meter and 400 meter individual medley) and one silver in the 800 meter freestyle.
Sweden's Therese Alshammar equaled the record of women's overall medals by winning silver in the 100m butterfly to match the 17 achieved by former U.S. swimmer Jenny Thompson.
Felicity Galvez won the race in a championships-record time of 55.43 to retain her title and give Australia a first gold of the competition.
China's Jing Zhao also set a new best time in winning the 50m backstroke in 26.27, while world record-holder Rebecca Soni of the U.S. set another milestone in the 200m breaststroke as she clocked 2:16.39 to clinch a hat-trick of golds in the discipline.