ZHENGZHOU, China - Chinese swimming star Sun Yang has shrugged off the row and proved he was back on track with world class results at the National Championships.

The Olympic 400m, 1,500m freestyle and 4x100m freestyle relay champion at the London Games kept a good form at the National Championships by collecting the 200m, 400m, and 800m titles in four days.

Sun Yang before the 200m freestyle finals in Zhengzhou, Henan province, on April 3, 2013. [Photo/Xinhua]

Sun established an early lead in the 800m free final Thursday and won the event in 7:48.60, which was the second fastest time of the year, as Olympic 1,500m runner-up Ryan Cochrane just timed a world best 7:43.61 on Wednesday's Canadian world-title trials.

Sun was satisfied with the time, "I'm not in my best, but the time was OK," he said. "I just swam under my rhythm and I hope I can make better result at the Worlds."

"Cochrane will be my biggest rival," he added. "I have not think about the world record, but I do hope my 400m can be faster."

Sun, runner-up in 200m free at the London Olympic Games, breezed to a 1:44.99 victory and set the fastest time of the event so far this year on Wednesday, which was just 0.06 second outside the time in which he match South Korean swimmer Park Tae-hwan for Olympic silver at London 2012. The Olympic gold medal was taken by French Yannick Agnel in 1:43.14.

The 21-year-old also claimed the 400m free in an Olympic podium result 3:42.93, almost two seconds faster than the time 3:44.69 making by the Olympic bronze medallist Peter Vanderkaay of the United States and the fastest time of the year so far. It was also his first match since reuniting with his long-time coach Zhu Zhigen.

After finding a new girlfriend since returning from the London Olympics, the balance couldn't be reached between Sun's personal life and swimming career. The 10-year-long relationship between Sun and Zhu turned sour after the swimmer reportedly asked for a new coach earlier this year. The 56-year-old coach disapproved Sun's love affair and he believed too many commercial activities had taken a toll on Sun's training.

Sun was suspended from all commercial activities in February for breaching a "series of team rules" and had one month's training allowance withheld.

However, Sun apologized to the coach and resumed training in March after been out of systematic training for over two months.