BARCELONA, Spain - The sixth day of action in the pool at the Barcelona world championships ended on a high note with a thrilling men's 4x200 relay in which Ryan Lochte won his 15th world championship gold medal, but which will also be remembered for the stunning swim off Sun Yang, who came from nowhere to give China what had looked like an impossible bronze medal.

The race was expected to be a contest between the Americans, the Russians and the French with the French side led by Daniel Agnel aiming to get a flying start, although Daniala Izotov had put the Russians in front.

Team China pose with their bronze medals at the men's 4x200m freestyle victory ceremony during the World Swimming Championships at the Sant Jordi arena in Barcelona August 2, 2013. From left: Li Yunqi, Wang Shun, Hao Yun and Sun Yang.  [Photo/Agencies]

Lochte then produced a strong second leg to give the Americans the lead, despite having already raced twice in the evening to give Charles Houchin a half second advantage in the third leg.

Ricky Berens was in control for America, with the Russians second and the real race between France and Japan for third until Sun Yang appeared on the scene.

The man who has already gold medals in the 400 and 1,500 medals was fifth when he got into the water, over two seconds behind the French, but produced the best split of the race to swim his final leg in 1:43.96 and give China a miraculous bronze medal.

Sun must be wondering whether or not he could one day compete in the 200 meters freestyle as well as the 400, 800 and 1,500 meters, because on Friday's form he would be unstoppable.