Roger Federer was eliminated from the Rome Masters after suffering a shock 1-6 6-3 7-6 (8-6) defeat to French outsider Jeremy Chardy.
The 17-time grand slam winner was returning to action following the the birth of his twins and lost out in a dramatic second round contest which lasted over two hours.
Chardy looked to have blown his chance as he squandered a 4-2 lead in the third set and again failed convert after going ahead by the same scoreline in the deciding tie-break.
But the world No 47 toughed it out, saving a match point with an extraordinary cross-court forehand winner before wrapping up the victory shortly afterwards.
Federer was playing for the first time since his defeat in the final of the Monte Carlo Masters a month ago but showed little signs of rust as he raced through the opening set.
Chardy battled back in the second, however, breaking his opponent in the fourth game and holding on to close out the set.
And the Frenchman raised the probability of a major shock when he broke the serve of an error-prone Federer again in the decider.
Chardy even earned a break point which would have moved him 5-2 ahead with a service game to follow, but Federer dug deep and managed to stay in the match.
The Swiss player then claimed a break of his own and clawed himself back on level terms as high winds at the Foro Italico played havoc with a number of rallies.
Federer seemed to have the momentum on his side heading into the breaker but was forced to fight back again after going 4-2 down.
It seemed as though the 32-year-old would survive the huge scare when he brought up match point, but Chardy saved it in amazing style before going on to complete the upset.
Nadal edges thriller
Sixth seed Tomas Berdych enjoyed a safe passage into the last 16 as he overcame Dmitry Tursunov 6-4 6-3, while Ivan Dodig had an even more comfortable time of it as he beat Lukas Rosol 6-1 6-2.
Jo-Wilfried Tsonga, seeded 11, needed two tough tie-breaks to get past Kevin Anderson as he bested the South African 7-6 (16/14) 7-6 (7/5).
Grigor Dimitrov was also made to work hard before ousting Ivo Karlovic 7-6 (7/3) 6-4, while Tommy Haas overcame Igor Sijsling 7-6 (8/6) 6-1.
Ernest Gulbis had to come from a set down to book his place in the third round as he beat France’s Stephane Robert 6-7 (1/7) 6-4 6-3.
Andrey Golubev was forced to retire from his clash with Mikhail Youzhny when his opponent was 7-5 4-1 ahead and Youzhny will now face top seed Rafael Nadal who came through a thriller against Gilles Simon in the night match.
Nadal looked on course for a straight sets win after taking the opener on a tie-break and then moving into an early 3-0 lead in the second.
But Simon fought bravely and, after breaking back and then saving a match point, squared the contest after winning a second tie-break.
But Nadal eventually wore down his man in the decider, breaking twice to complete a 7-6 (7/1) 6-7 (4/7) 6-2 victory in three hours and 18 minutes.