Grigor Dimitrov was soundly beaten in straight sets in the first round of the French Open after finding the service of giant Croatian Ivo Karlovic too hot to handle.
The 11th seed from Bulgaria, who reached his first grand slam quarter-final in Australia this January, was beaten 6-4 7-5 7-6 (7-4).
Karlovic fired 22 aces and wasn't broken by Dimitrov, who won the Bucharest clay-court title this spring and was a semi-finalist at the Rome Masters.
The 6ft 11in Karlovic is always a man players like to avoid and he has been showing rare good form on clay having reached the final in Dusseldorf last week.
His record at Roland Garros leaves something to be desired, Karlovic having won only two matches at Roland Garros in his career and none since 2007.
But his forehand was on fire as well as his serve and after the match Dimitrov admitted that he couldn't find any rhythm on Court one.
"It's never easy to play against Ivo," said the 23-year-old. "Of course, it's a big disappointment for me, losing first round of the tournament. I like my chances here. I've been playing good tennis on the clay courts, so I don't want to be too disappointed. It happened.
"I just couldn't find the rhythm, and I couldn't achieve any of the little opportunities that I had in the match. So it's something to obviously learn from, but in a way it was one of those days that you can't control anything."
The 35-year-old Karlovic has now equalled his best French Open performance and next faces Austria's Andreas Haider-Maurer.
Meanwhile, Spanish fifth seed David Ferrer, last year's runner-up to Rafael Nadal, began his 12th Roland Garros by coasting past Igor Sijsling of the Netherlands, 6-4 6-3 6-1.
Ferrer, 32, has reached the quarter-finals or better at his last nine majors.
French No 1 Richard Gasquet also made it through to to the second round after a 6-26-1 7-5 win against Bernard Tomic.
Gasquet was playing competitive tennis for the first time since March having been an injury doubt for the French Open until days before the tournament, but cmae through with ease against his Australian opponent.
Last year's quarter-finalist Tommy Haas is out of the event after he retired when 5-2 down in the first set against Jurgen Zopp.