The FIA's Contract Recognition Board has ruled in favour of McLaren on Oscar Piastri, allowing the Australian to take a seat with the team on the grid from 2023.
Alpine and McLaren were locked in a battle over the services of the 21-year-old, who was a member of Alpine's junior programme and held reserve status with the team this season.
Fernando Alonso's announcement that he would be leaving Alpine for Aston Martin sparked a domino effect in the market, with Alpine then announcing Piastri would take a seat next year.
However, Piastri then took to social media to deny he had agreed to race for the team, with it widely understood he had instead reached an agreement with McLaren - who confirmed Daniel Ricciardo would leave at the end of the season.
Both teams believed they had a valid contract for Piastri, with the case then being heard by the CRB this week - who have now ruled in favour of McLaren.
"The only Contract to be recognised by is the Contract between McLaren Racing Limited and Mr Piastri dated 4 July 2022. Mr Piastri is entitled to drive for McLaren Racing for the 2023 and 2024 seasons," the CRB said.
McLaren swiftly announced Piastri as their 2023 driver alongside Lando Norris and Piastri spoke of his delight at joining the team.
"I'm extremely excited to be making my F1 debut with such a prestigious team as McLaren and I'm very grateful for the opportunity that’s been offered to me," he said.
"The team has a long tradition of giving young talent a chance, and I'm looking forward to working hard alongside Lando to push the team towards the front of the grid. I'm focused on preparing for my F1 debut in 2023 and starting my F1 career in papaya."
Alpine will now be on the hunt for a driver to sit alongside Esteban Ocon next season, with widespread reports Pierre Gasly will join from AlphaTauri, ending his long association with Red Bull, and the team said an announcement on their line-up would be made in due course.
"BWT Alpine F1 Team thanks the Contract Recognition Board (CRB) for convening on Monday and we acknowledge the decision they have made," they stated on Twitter.
"We consider the matter closed on our side and will announce our full 2023 driver line-up in due course. Our immediate focus is the Dutch Grand Prix and securing points in our fight for fourth in the Constructors' Championship."
Alpine is fourth in the Constructors' Championship on 115 points, 20 points ahead of McLaren.