Rafael Nadal described his emphatic defeat to Fabio Fognini in Saturday's Monte Carlo Masters semi-final as "one of the worst matches on clay in 14 years".
Nadal, an 11-time champion in Monaco, looked to be putting together a routine victory when he took a 3-1 lead, despite being broken in the first game.
However, a combination of wayward ball-striking from Nadal and a fine performance by Fognini saw the Italian world No 18 stun the second seed 6-4, 6-2. Fognini is just the fourth player to beat Nadal at the Monte Carlo Masters and is one of seven to claim more than one win over the 17-time grand slam champion on clay.
"I played one of my worst matches on clay in 14 years," said Nadal. "It's difficult to find any positives – I deserved to lose.
"The vision is clear," added 32-year-old Nadal who was playing his first tournament in a month after opting to rest his troublesome knees.
"I played a very bad match against a good player. In that situation, you have to lose.
"I had a bad feeling, it was a tough day. I'm coming from low moments in terms of injuries, and in terms of the mental side it has not been easy to accept all the things that have been going on during recent weeks.
"Everything was wrong. I always expect the best. But you have to be ready to accept the negative things and today was a negative day."
For 31-year-old Fognini, based just over the border in San Remo, it was a fourth career win over Nadal and third on clay.
"I had a really good week, did some good work," said the Italian. "I was born near here, I know how to play on clay. This will be the final that no-one expected, I just hope to recover well and be ready."
Fognini, cheered by thousands of compatriots on Centre Court, broke Nadal three times in a 55-minute opening set.
Nadal saved three match points while trailing a set and 5-0 as he broke Fognini in a last-gasp effort. But the 13th seed would not be denied, earning another pair of chances in the eighth game and claiming victory with a forehand winner down the line.
"I'm calm, I want to enjoy my victory," Fognini said after reaching his first final at the Masters 1000 level. "I've beaten Rafa on clay, I'm really happy, it was windy and tough to play."
Fognini will contest his first Masters 1000 final against Dusan Lajovic after the Serbian produced a rousing fightback to beat Daniil Medvedev 7-5, 6-1.
"Of course it's a surprise to play Lajovic, but he's playing good," Fognini said.
Earlier, Lajovic had trailed 3-0 and 5-1 against Medvedev in the opening set before going through the gears.
The 10th-seeded Medvedev could not hold the pace as winds swept across centre court and Lajovic quickly moved 4-0 up in the second set against a frustrated opponent, who bowed out on the second match point.
"It was an incredible match today," said world No 48 Lajovic, the lowest-ranked player to reach the final here since Hicham Arazi in 2001.
"I had the worst nightmare, falling down 5-1, but I won 10 games in a row, so I was able to find my rhythm and my game.
"In windy conditions like today, it was impossible to play real tennis and in the end I was able to hit my forehands better than him. I'm still unaware of my achievement in Monte Carlo."
