Alcaraz and Sinner to face off in Monte Carlo final
Alcaraz saw off Vacherot 6-4, 6-4 to stay on track to defend his title and set up a Sunday showdown with Sinner for the world number one ranking.
It will be the first meeting this season between the world's top two players and will decide who will be world No.1 come Monday when the new ATP rankings are released.
"I think it's the dream spot for everyone I would say. I'm fighting for a second Monte Carlo title, he's fighting for his first one," said Alcaraz of Sunday's final.
"It's going to be a really special one. The No.1 is on the line, which will make tomorrow even more special."
The 22-year-old Alcaraz is trying to keep hold of top spot and holds a 10-6 lead over Sinner in the head-to-head series.
Alcaraz broke Vacherot three times to wrap up victory in 84 minutes and is bidding for his third title of the season after winning the Australian Open and in Doha.
"I'm just happy to win this really difficult match against Valentin," said Alcaraz.
"He's playing great tennis with a lot of confidence right now, playing in his hometown. It was really tough to get the win, but I'm really excited about my first meeting with Jannik in 2026."
Sinner dispatches Zverev
Sinner eased his way into the Monte Carlo final for the first time with a clinical 6-1, 6-4 semi-final win over Alexander Zverev earlier on Saturday.
The 24-year-old Italian becomes the first player to reach all three finals of the season's first three Masters 1000 events since Novak Djokovic in 2015.
Roger Federer, in 2006, and Rafael Nadal, 2011, are the only two other players to achieve the feat.
"I'm very happy," said Sinner.
"We came here trying to give myself some feedback (on clay) and now finding myself in the final means a lot to me."
Sinner said he had felt in top form right from the outset of the match against his German opponent, ranked third in the world.
"Obviously every match, every day is different, so I'm very happy about today's performance. I felt really solid from the beginning.
"When you are a break up straight away, it changes the dynamic of the match, so very happy and let's see what's coming in the final."
As in Indian Wells and Miami, Sinner, 24, had the measure of Zverev who has not prevailed in their meetings since the round of 16 at the US Open in September 2023.
Extremely aggressive from the start, Sinner blew the German away in the opening set, breaking him three times and wrapping it up in 34 minutes.
In the second set, Zverev put up more resistance, finding his first serve again, but he still had to battle every time to hold.
He finally folded after 82 minutes on another blistering forehand from Sinner, who has lost only one set in his last 21 matches at Masters 1000 events.