'What is happening': Tennis world in shock over US Open 'carnage'

The tennis world is in a state of shock after four top 10 male stars crashed out of the US Open in the opening round.

Dominic Thiem (4), Stefanos Tsitsipas (8), Karen Khachanov (9) and Roberto Bautista Agut (10) all suffered unthinkable losses in New York on Tuesday.

Thiem, who is widely regarded as the most likely young gun to win a slam outside of Roger Federer, Rafael Nadal and Novak Djokovic, went down in four sets to Thomas Fabbiano of Italy.

The two-time French Open runner-up and a US Open quarter-finalist last year, was beaten by the same player who dispatched Greek sixth seed Tsitsipas in the first round at Wimbledon.

Their quarter of the draw is suddenly wide open after the exit of its four top-ranked players.

The top seed remaining in the quarter is France's 13th-seeded Gael Monfils.

Thiem and Tsitsipas’ losses meant they both suffered first-round defeats in back-to-back grand slams after the same happened at Wimbledon.

The crazy results left fans and pundits stunned, with many pointing out that it opens the door for Nick Kyrgios to swoop.

It also means Nadal's path to the US Open crown becomes much easier.

The only top-10 rivals remaining in Nadal's half as he chases a 19th grand slam title are still in his quarter of the draw, however, in German sixth seed Alexander Zverev.

Tsitsipas melts down

Tsitsipas crashed out having unleashed a tirade against the chair umpire, who he called a "weirdo."

World No.43 Andrey Rublev, who two weeks ago earned the biggest win of his career when he beat Federer in the third round at Cincinnati, attacked Tsitsipas with a barrage of forehands and broke his opponent five times in the 6-4 6-7 (7-5) 7-6 (9-7) 7-5 win.

But Tsitsipas, whose best showing at a grand slam came this year in Australia where he reached the semi-finals, received a coaching warning for his father's behaviour early in the third set at Louis Armstrong Stadium.

The Greek, one game after receiving a time violation in the fourth set, then became furious when the umpire would not allow him extra time on the changeover to change his bandana.

An angry Tsitsipas told the umpire: "You're a weirdo, you're all weirdos."

He also asked to be given a point penalty, which the umpire granted at 3-4 before Rublev went on to hold to love.

Bautista Agut and Khachanov crash too

As for Bautista Agut, he was upset 3-6 6-1 6-4 3-6 6-3 by Kazakhstan's Mikhail Kukushkin.

Bautista Augut, who reached the semi-finals at Wimbledon last month, was broken seven times by Kukushkin as he exited the year's final grand slam in the opening round for the second consecutive year.

It was Kukushkin's first victory over the Spaniard in four career meetings.

Russian ninth seed Khachanov lost to Canada's Vasek Pospisil in five sets 4-6 7-5 7-5 4-6 6-3.

Pospisil, who has fallen to 216th in the world rankings after having back surgery in January that sidelined him until Wimbledon, fired 15 aces and broke Khachanov four times during the near four-hour encounter.

with agencies