World number one Carlos Alcaraz suffered a shock third round defeat in the Italian Open at the hands of unheralded Hungarian Fabian Marozsan, losing 6-3, 7-6 (7/4) on Monday.

The 20-year-old Spaniard had come into the tournament on the back of wins in Barcelona and Madrid but was outplayed by Marozsan, who is ranked 135^thin the world.

Marozsan, 23, won the final six points of the second-set tiebreaker to hand US Open champion Alcaraz a wake-up call with the French Open starting in less than a fortnight.

Marozsan, who next plays Borna Coric for a place in the quarter-finals, had not won a match on the ATP Tour prior to the tournament — indeed this is the first time he has qualified for the main draw at a tournament on the Tour.

“Everything was perfect today, I was doing my job,” the winner said. “I cannot imagine this win, even if it was my dream last night.

“I thought I might win a few games or a set.

“I tried to hit back every ball, I was trying to do my best.”

Marozsan produced 24 winners in a victory which took an hour and three quarters.

“I had hoped I could do something special,” he said. “Now I’ve just beaten the best in the sport so I’m very happy.”

Alcaraz now stands 30-3 on the season as he prepares to head to Roland Garros as top seed for the first time at a Grand Slam.

In other results at the ATP-WTA tournament, sixth seed Andrey Rublev defeated Spain’s Alejandro Davidovich Fokina 7-6 (10/8), 6-3. (AFP)