Zhang Zhizhen sent fifth seed Casper Ruud crashing out of the US Open on Wednesday, creating tennis history by becoming the first man from China to beat a top-five player.

The 26-year-old from Shanghai -- ranked 67th in the world -- produced the match of his life to defeat last year's US Open finalist 6-4, 5-7, 6-2, 0-6, 6-2 in 3hr 19min.

Zhang's victory was the first time any male Chinese player has beaten a player ranked in the world's top five.

Zhang will face Australia's Rinky Hijikata in the third round on Friday, bidding to reach the last 16 of a Grand Slam for the first time.

Tempers flared after Ruud had levelled the match at two sets apiece with a 6-0 fourth set.

Zhang left the court for several minutes to take a toilet break and change clothes in a move that clearly disrupted Ruud's momentum.

The Norwegian was broken immediately in the first game of the final set, and a frustrated Ruud complained angrily at the chair umpire, accusing him of failing to enforce time limits.

"Why don't you do anything?" Ruud yelled at the umpire. "You follow the rules clearly some times then other times you don't give a shit. Why don't you do anything?"

With Ruud unravelling, Zhang rammed home his advantage. He broke again in the fifth game to take a 4-1 lead and then held for a 5-1 lead.

Ruud held serve to close the gap to 5-2, but Zhang would not be denied, producing a superb backhand volley on match point to seal victory.

rcw/mw