Richard Gasquet produced one of the best matches of his career to hit back from a set down to defeat world number three Roger Federer 4-6, 7-6 (7/2), 7-6 (7/4) at the Rome Masters on Thursday.
It was the French 16th seed's first victory over Federer since his breakthrough result in 2005 in Monte Carlo when he beat the great Swiss in the quarter-finals as an 18-year-old.
Record 16-time Grand Slam winner Federer said he should have won.
"I had a lot of good chances at a set, 4-3 and serving and then at 4-4 and 15-40 (on Gasquet's serve)," said the 29-year-old.
"That's how it goes sometimes, I thought I was playing well and then in the third I wasn't playing at all, it's a disappointing match for me.
"It was tough to play out there, it was a slippery court. Richard started to play better as the match went on. In particular he was serving better, my level went down and Richard made it worse.
"It was tough, I never felt I was probably going to win the (third set) breaker, it's not fun to play that way."
The first set began with Federer winning the first 10 points and Gasquet followed that up with 10 in a row himself.
The upshot was they came out on level terms but at 3-3 and deuce a Federer inside-out forehand winner cross court and backhand winner down the line gave him a break, after which he served out the set.
Having taken two out of two break opportunities in the first set, Federer needed no second invitation in the fifth game of the second.
Gasquet wasted a short ball with a poorly-executed drop shot which Federer pounced on and forced an error from the Frenchman.
That produced two break points and a long forehand from Gasquet handed the Swiss master the lead.
However he broke back in the eighth game with a low backhand volley winner after a quick-fire exchange at the net.
Crucially, Gasquet then held from 15-40 in the next game and forced a tie-break.
The Frenchman earned two mini-breaks and a 5-2 lead when first a Federer backhand drifted long and he then scorched a cross-court forehand beyond his opponent's reach.
A netted backhand from Federer and a service winner made it one set all.
The decider also went to a tie-break and after trading a pair of mini-breaks, Gasquet got his nose in front when Federer missed a backhand.
A forehand wide brought up match point and then another backhand long gave Gasquet a deserved victory.