'Oh my God': Tennis world erupts over 'extraordinary' moment

Daniil Medvedev and Ugo Humbert have played out one of the rallies of the year, stunning fans at the Hamburg Open.

Medvedev lost his first match since reaching the US Open semi-finals as he was beaten 6-4 6-3 on Tuesday by the unseeded Frenchman.

‘DIFFICULT DECISION’: Tennis champ’s shock announcement

‘DISGUSTED’: Nadal dragged into French Open virus drama

The top-seeded Medvedev was a break up at 4-3 in the first set but was broken twice in a row by Humbert, who is ranked 36 places below the Russian at 41st.

And one rally at 5-4 in the first set encapsulated Humbert’s shock win to a tee.

The 32-shot rally lasted nearly a minute, with both men scrambling to stay in it when they looked like they would lose it on multiple occasions.

Humbert finally put a winner away on the 32nd shot of the rally, leaving Medvedev and commentators in shock.

“You’ve got to be kidding me,” one commentator exclaimed on Tennis TV.

“Not only is that the point of the day it might be the point of the week. Extraordinary from both.”

Another commentators added: “I thought Humbert had won that point about four times.”

“A phenomenal rally from both men.”

Fans also flocked to social media in awe.

This was Medvedev's only clay-court warm-up ahead of the French Open.

He hadn't played on clay for 16 months since a first-round defeat at last year's French Open and played only at hard-court tournaments in the last 14 months.

Humbert next faces qualifier Jiri Vesely.

Gael Monfils joins Medvedev as shock losers

Third-seeded Gael Monfils was another early casualty, losing 6-4 6-3 to 103rd-ranked Yannick Hanfmann.

Hanfmann needed just 1 hour, 13 minutes to wrap up the win and the German will next face Cristian Garin, who swept past Kei Nishikori 6-0 6-3.

Garin is bidding to win his third trophy on clay this year.

Fourth-seeded Roberto Bautista-Agut won 6-4 6-3 against two-time defending champion Nikoloz Basilashvili to set up a second-round meeting with Dominik Koepfer.

The 32-year-old Bautista Agut, who became a father for the first time last week, triumphed in 1 hour, 25 minutes.

The Spaniard next faces Koepfer for a place in the quarter-finals after the German defeated Yoshihito Nishioka 7-6 (7-0) 4-6 6-1.

Fabio Fognini built up momentum after a slow start to oust Philipp Kohlschreiber 4-6 6-1 7-5.

The sixth-seeded Italian will play either Casper Ruud or Benoit Paire in the second round.

Canada's Felix Auger-Aliassime defeated Lorenzo Sonego of Italy 6-2 7-6 and will next play Alexander Bublik, who beat Albert Ramos-Vinolas 6-2 7-6.

with AAP