Sun Yang of China reacts after competing in the men's 800m freestyle heats during the World Swimming Championships at the Sant Jordi arena in Barcelona, July 30, 2013. [Photo/Agencies]

BARCELONA - China's Sun Yang finished second on Tuesday morning heats of men's 800 meters freestyle at the FINA World Championships.

Sun Yang was leading the third heat since the start ahead of Tunisia's Oussama Mellouli, gold medalist in 5 km open water in Barcelona, and Italia's Gregorio Paltrinieri who finished fifth and seventh in the preliminaries respectively.

Sun, who took gold medal in 400 meters freestyle on Sunday, had the second best time on Tuesday's morning event, finishing the 800 meters in 7:49.37 after the United States' Connor Jaeger, who clocked 7:49.28.

The Palau Sant Jordi also host men's 50 meters breaststroke preliminaries where South Africa's Cameron Van Der Burgh finished first in 26.78, followed by Brazil's Felipe Lima and New Zealand's Glenn Snyders in 27.11 and 27.27 respectively.

Sun Yang of China (C) is seen underwater as he competes in the men's 800m freestyle heats during the World Swimming Championships at the Sant Jordi arena in Barcelona, July 30, 2013. [Photo/Agencies]

World record holder Van Der Burgh took silver medal in men's 100 meter breaststroke on Sunday, while Lima won bronze medal. Christian Sprenger, world champion on Sunday finished fourth on Tuesday's preliminaries.

Meanwhile, France's and gold medallist in women's 400 meters freestyle in London 2012 Camille Muffat clocked the best time in women's 200 meters freestyle preliminaries finishing the race in 1:56.53.

She was followed by Hungary's Katinka Hosszu and Italia's and world record holder Federica Pellegrini. US four-time Olympic gold medallist Missy Franklin finished fifth with 1:56.90.

In men's 200 meters butterfly preliminaries, American Clary Tyler finished first clocking 1:56.03, followed by South Africa's Chad Le Clos (1:56.21) and Tyler's compatriot Tom Luchsinger. Meanwhile, China's Yin Chen and Wu Peng finished fifth and tenth respectively.

After Tuesday morning preliminary session, the Palau Sant Jordi will host five finals in the evening: men's 200 meters freestyle and 100 meters backstroke, and women's 100 meters backstroke, 1,500 meters freestyle and 100 meters breaststroke.