The Australian:

Australia's Olympic champion Mack Horton has lost round two of his ongoing stoush with china's Sun Yang in 400m freestyle at world championships in Budapest.

Sun remained his world title in 3min 41.38sec, fractionally faster than Horton's winning time at last year's Olympics, and then celebrated as if he had won both gold medals.

ABC News:

Mack Horton beaten by Sun Yang in world swimming championships 400m final.

Asked about Sun,Horton said:'I don't know if it is a rivalry, I think it is a rivalry between clean athletes and athletes have tested positive.'

However, Sun dominated the medal race to finish more than two body lengths ahead of Horton and claim his eighth overall world titles gold.

The Sydney Morning Herald：

Olympic champion Mack Horton insisted his slow time hurt more than arch nemesis Sun Yang denying him 400m freestyle gold at the world swimming championships at Budapest on Sunday night.

Earlier,the 400m freestyle medal race was billed as "the War on Water II" after Horton dismissed Sun as a "drug cheat" at the Rio Olympics before upsetting the defending champion to claim 400m.