Kazan, Aug 10 (IANS): China's swimming superstar Sun Yang has apologised for his withdrawal from the men's 1,500m freestyle final here.

The world record holder and Olympic champion quit the 1,500 metres freestyle final on the last day of the world swimming championships on Sunday, citing heart discomfort, reported Xinhua.

The 23-year-old was the hot favourite for the title but did not show up at the starting blocks despite having warmed up for the race. Sun appeared at the last ceremony of the Worlds, receiving the Male Swimmer of the World Championships award. He attended the press conference after the ceremony.

"I am sorry that I failed to compete in the 1,500m final," Sun, who finished third in the heats on Saturday, said.

"I had to pull out of the final as I felt a heart discomfort before the race," said Sun, winner of the 400 metres freestyle and finishing second in 200 metres.

"I didn't feel good after the 800m final but I really wanted to take part in the 1,500. So I came to warm up today, but after the warm-up, I was still not feeling good."

Italian Gregorio Paltrinieri won the 1,500 metres race in a European record of 14:39.67 minutes, while American Connor Jaeger took silver in 14:41.20 minutes with Ryan Cochrane of Canada third in 14:51.08 minutes.

"I am happy for the winner," said Sun. "I also noticed his time. I think I can compete with him in Rio (Olympic) Games, and if I am in good form, I still think I will be the best."

Sun had served a three-month ban in 2014 after testing positive for stimulant trimetazidine which was mistakenly used to treat his heart condition.