By Iain Rogers
BARCELONA (Reuters) - Australia's Brenton Rickard provided the first surprise of the world swimming championships when the 2009 gold medalist failed to make the semi-finals of the men's 100 meters breaststroke on the opening morning of racing in Barcelona on Sunday.
Rickard, a former world-record holder who was sixth at the London Olympics last year, could muster only the 17th fastest time at the hilltop Palau Sant Jordi pool, almost a second slower than compatriot Christian Sprenger who was quickest with a time of 59.53 seconds.
Russian Kirill Strelnikov was second fastest in 59.80 seconds ahead of Fabio Scozzoli of Italy, who finished in 59.88, tied with the 2004 and 2008 Olympic champion in both 100m and 200m breaststroke, Japan's Kosuke Kitajima.
South African Cameron Van Der Burgh, the world-record holder and the Olympic champion in London who is coming back from a knee injury, was seventh quickest in 1:00:02.
The semi-finals are later on Sunday and the final is on Monday.
China's Sun Yang and Frenchwoman Camille Muffat moved safely through to the 400m freestyle semi-finals as they sought to replicate their Olympic triumphs in London in the final later on Sunday.
Sun, aiming to become the only man after Australian Grant Hackett to win gold in 400m, 800m and 1,500m at the same world championships, was more than a second quicker than Canada's Ryan Cochrane, with Jordan Harrison of Australia third.
Muffat will have to pass what promises to be a stern test from American teenager Katie Ledecky, who may have Italian Federica Pellegrini's world record from the 2009 championships in Rome in her sights.
Ledecky returned the fastest time in the heats of 4:03:05 more than a second ahead of Spain's Melanie Costa Schmid (4:04:20) and Briton Jazmin Carlin (4:04:85). Muffat was down in sixth on 4:05:53.
Pellegrini also won the 400m freestyle in Shanghai two years ago but is focusing on the 200m backstroke in Barcelona.
Olympic champion and world-record holder Dana Vollmer of the United States was quickest in the heats for the women's 100 meters butterfly ahead of Swede Sarah Sjostrom, Canada's Katerine Savard and Alicia Coutts of Australia.
Lu Ying, Olympic silver medalist behind Vollmer in London, went through to the semis later on Sunday in 12th.
Aside from the 400m freestyle finals, medals will be decided in the men's and women's 4x100m relays later on Sunday.
(Editing by Clare Fallon)