MONACO (AP) " Defending champion Rafael Nadal beat David Goffin 6-3, 6-1 to move within one more win of a 10th Monte Carlo Masters title and first of the season on Saturday.
Nadal will play 15th-seeded Albert Ramos-Vinolas in an all-Spanish final after the latter beat Lucas Pouille of France 6-3, 5-7, 6-1.
Although the score suggests a comfortable win for Nadal, Goffin's momentum was halted by a controversial decision by chair umpire Cedric Mourier in the sixth game. Goffin was asked to replay game point after holding his serve for what would have been a 4-2 lead.
"All of a sudden you have a mistake like the chair umpire did, it's really tough," Goffin said. "When you have a mistake like this, you have to give more energy again to come back into the game. It was maybe too much."
Goffin was incensed at what he basically called an improvised decision by Mourier to point at a mark that didn't correspond.
"He just showed me something, I don't know what," Goffin said. "I saw on his face that he was nervous, he wasn't sure."
Nadal's celebrations were muted after he clinched victory on his third match point and he sympathetically hugged Goffin at the net. Nadal shook Mourier's hand, but Goffin did not and walked straight past him to pick up his bags.
"I have nothing against Cedric, he's a very nice guy," Goffin said. "But he makes mistakes."
Four years ago, it was a perplexed Nadal arguing with Mourier after he made an incorrect call during Nadal's third-round win against Russian Mikhail Youzhny at the Madrid Masters.
Nadal is through to his fourth final of the season. He lost the other three, two of them to Roger Federer, including at the Australian Open.
"I know that I had to defend almost all my points at this beginning of the season," Nadal said. "Having all these great results I am having allows me to still have the position in the top eight of the rankings."
Nadal and the 10th-seeded Goffin met for the first time, and the momentum of the semi effectively turned on the overrule since Goffin was playing the better tennis at the time.
After being taken to deuce three times Goffin finally held " or so he thought " when Nadal hit a return too long.
It seemed evident that the ball landed out, but Mourier overruled and called it in, meaning the point had to be replayed. Goffin could not believe it and nor could the crowd, who jeered loudly.
Mourier came down from his chair to speak to Goffin. Their exchange in French " shared on social media " went like this:
"No, it's over there," Goffin tells Mourier, pointing to a mark to the left of the court.
"Well, I think it's that one," Mourier says, leaning forward and pointing centrally.
"No, you can't say that, it's completely over here," Goffin replies raising his voice, pointing again.
"Well, listen, then I'm wrong but ..."
"Oh, it can't be true!" says an exasperated Goffin, putting his hands on his head.
Video replays showed it was out, but with no Hawkeye technology used on clay, the Belgian player could not challenge the initial call. Still, the umpire effectively overruled a line judge in a far better position than him.
"He was play-acting, like he had made the right decision," Goffin said. "(But) it was blatant."
When Nadal and Goffin resumed, Nadal was booed when he won points, and the crowd began chanting, "David, David." But Nadal eventually broke him in the game.
Goffin continued to complain to Mourier after the set. Nadal went off court for a break and jeers filled the air when he came back on.
"I receive huge support from the crowd all around the world. Today, I don't know why," Nadal said. "For me (it) is sad, especially in a place that I love."
Nadal, a nine-time French Open champion, is not convinced of Hawkeye's accuracy and doesn't want it on clay.
"If we made that happen, then Hawkeye will be in trouble," he said.
The other finalist, Ramos-Vinolas, has lost his two previous matches against Nadal, has reached his first Masters final, and won only one title. Nadal is bidding for his 70th.
Earlier, Pouille was 3-0 down in the deciding set when he needed treatment to his lower back and hips. His power went after that.