GWANGJU, South Korea - Triple Olympic champion Sun Yang started his fifth race at the 18th FINA World Swimming Championships on Tuesday morning as he placed eighth to squeeze into the men's 800m freestyle final.

As the defending champion, Sun also needs to swim the 200m final as the first race among all the evening session contested later on Tuesday.

Sun clocked a time of seven minutes 48.12 second for the eighth place while Italy's Gregorio Paltrinieri topped the 800m freestyle with a 7:45.70.

"I tried to swim as comfortable as possible in 800m heat because I slept at 2 am, got up at 7:40 am this morning. It was my fifth time to swim while most of the others were having their first. They were in better shape and had more energy than me," Sun said after 800m heat.

"My 200m free final is the first event tonight. I don't want to give up any event I compete in, no matter 200m or 800m, I try to balance the distances," the 27-year-old continued.

There is no other swimmer competing in 200m, 400m and 800m, except Sun Yang, who roared to a record four straight victory in men's 400m freestyle on Sunday.

"I try my best to swim in every race and I don't mind the medals or the rivals anymore. I like to compete and enjoy the races," he said.

Gregorio Paltrinieri of Italy, who won gold in men's 1,500m freestyle at Rio 2016, just competed in the open water for sixth in 10km and second in the mixed 5km relay in Gwangju.

"Maybe it is a good way to prepare for long-distance by swimming in the open water races but I am personally a little bit afraid of the jellyfish bites in the sea," Sun joked.