Canada's Amanda Reason had the fourth-fastest time in the women's 50-metre breaststroke semifinals. ((Francois Xavier Marit/AFP/Getty Images))

Canada's Amanda Reason swam a strong race to advance to the women's 50-metre breaststroke final at the world aquatics championships on Saturday, while fellow Canuck Annamay Pierse is in as well thanks to winning a swimoff over Russia's Valentina Artemyeva.

Reason, 15, got off to a blistering start and kept up with Yuliya Efimova of Russia and Australia's Sarah Katsoulis to finish third in her heat and fourth overall. Pierse, who was in the same heat as Reason, didn't get a good jump and struggled to keep up with the front-runners.

But Pierse, who won silver in the 200-metre breaststroke, was good enough to make it into a swimoff with Artemyeva.

Reason, who holds the world record in the 50-metre breaststroke, touched the wall with a time of 30.42. The time is 19/100ths off her world mark. Pierse and Artemyeva both finished in 30.92.

Australia's Katsoulis was fastest in the semis, with a time of 30.33.

Closest of margins

In the swimoff, Pierse edged out Artemyeva by 1/100th of a second to earn the last berth in the final. Pierse finished with a time of 30.98, just ahead of Artemyeva's 30.99.

Victoria Poon of Lasalle, Que., finished 13th in the women's 50-metre freestyle semifinal, and didn't advance.

Poon and Pierse also swam in the 4x100-metre medley relay final, along with Stratford, Ont.'s Julia Wilkinson and Audrey Lacroix of Pont-Rouge, Que.

A strong charge by Pierse in the second leg brought Canada among the bronze medal contenders, but the team couldn't sustain the pace and finished sixth.

China and Australia were way ahead of the pack, and the Chinese pulled off the upset and broke the Australians' world record in the process. China finished in 3:52.19, while Australia touched the wall in 3:52.58.

Both teams went under the Australians' old mark, which was 3:52.69.

Cochrane advances

Earlier in the day, Victoria's Ryan Cochrane advanced to the finals in the men's 1,500-metre freestyle, finishing third overall with a time of 14:56.56. Sun Yang of China was fastest in the preliminaries, clocking in at 14:54.54.

Zimbabwe's Kirsty Coventry broke her own world record on the way to winning the 200-metre women's backstroke title.

She led from the start of the race, and held off a challenge at the end by Russia's Anastasia Zueva to win gold. American Elizabeth Beisel took bronze.

Coventry finished in 2:04.81, lowering her old mark, set during the Beijing Olympics, by 43/100ths of a second.

Australian Marieke Guehrer got the program started with a win in the women's 50-metre butterfly final. She won by nine hundredths of a second over second-place Zhou Yafei of China, but couldn't best her world-record mark. Norway's Ingvild Snildal was third.

Cesar Cielo of Brazil capped a sweep of the freestyle sprints by out-touching world-record holder Frederick Bousquet of France for gold in the men's 50-metre freestyle. Frenchman Amaury Leveaux won bronze.

Lotte Friis of Denmark won gold in the women's 800-metre freestyle, finishing ahead of Briton Joanne Jackson in second and Italy's Alessia Filippi in third.