MONACO -- Fabio Fognini ended Rafael Nadal's long winning streak at the Monte Carlo Masters, stunning the defending champion 6-4, 6-2 Saturday to reach the final for the first time and hand Nadal his first defeat here since the 2015 semifinals.

The 13th-seeded Italian had beaten Nadal twice before on clay, and also once at the U.S. Open in five sets, but this was arguably the most impressive.

"I played one of my worst matches in 14 years," Nadal said. "We can talk about technical and tactical things, but on this kind of day things are just not there. It's difficult to find an explanation."

Not since the 2005 final, a best-of-five encounter which Nadal won in four sets, had the 11-time champion Nadal been beaten 6-0 in a set here. And Fognini came so close to doing just that.

He served for the match at 5-0 and 40-0, but Nadal saved three match points -- and some pride -- by breaking back and then holding.

"I was lucky to win the two games and to avoid the even worse score," Nadal said. "I was not thinking much. Just thinking about how bad I played today."

Serving again for the match at 5-2, Fognini hit a superb forehand down the line to clinch victory on his fourth match point.

Nadal's last defeat here was also in the semifinals, against Novak Djokovic four years ago. He had not lost a set at the clay-court tournament since conceding one in the second round against Britain's Kyle Edmund in 2017.

Fognini next plays unseeded Serb Dusan Lajovic in their first-ever meeting, and one few would have predicted happening here.

The 48th-ranked Lajovic staged a remarkable comeback from 5-1 down to beat 10th-seeded Daniil Medvedev 7-5, 6-1.

That match was a suitable appetizer to the higher drama which followed.

Nadal had dropped his first three service games Friday in his quarterfinal against Guido Pella, and the early signs were not good this time.

His first game against Fognini lasted 12 minutes, with Nadal saving four break points before conceding the first of six breaks of serve in the match.

In his quarterfinal and semifinal combined, Nadal conceded 23 break-point chances.

But whether Fognini, who previously lost 11 times to Nadal overall, could capitalize seemed uncertain.

The 31-year-old Italian can lose his temper on court, and it got the better of him in a bizarre incident during the fourth game.

With heavy winds swirling around the court, Fognini's towel flew off his seat and landed on the clay during the first point. He complained to the umpire, perhaps to get the point replayed, and then angrily put the offending towel into his drinks box.

Nadal broke him to love to lead 3-1, and Fognini got a warning for unsportsmanlike conduct.

Fognini irate, Nadal serving for a 4-1 lead -- another comfortable Nadal route to the final looked on.

But it's rarely straightforward for Nadal against Fognini, who broke back to 3-2 and then broke Nadal to love in the ninth game with some momentous shot-making.

Momentum was on Fognini's side, not to mention some luck.

Serving for the set at 5-4 and 30-30, his shot hit the net and turned into a perfect drop shot.

Fognini raised both arms in apology, and then superbly put away a volley at full stretch on the next point to clinch the set.

Playing spectacular tennis, Fognini was in full flow and he hit a delightful two-handed, backhand cross-court winner to break at the start of the second set.

Nadal is usually the undisputed crowd favourite on the French Riviera, but shouts of "Fabio, Fabio, Fabio" rang out at the Monte Carlo Country Club.

Many Italian fans likely made the short trip along the coast from nearby San Remo -- where Fognini grew up.

When the usually erratic Fognini held to love for a 2-0 lead -- with an ace -- they knew something special was happening.

Earlier, Lajovic won 10 straight games to lead 4-0 in the second set before Medvedev finally again held serve. But after saving one match point, the Russian player tamely hit a return long on his opponent's next opportunity.

It could have been an all-Serb semifinal but Medvedev knocked out the top-ranked Djokovic in Friday's quarterfinals.

The 28-year-old Lajovic was ill before the tournament and said he needed antibiotics to recover.

He struggled to describe his surprise run.

"Incredible ... Unreal," he said, before settling on "It's been a great week."