Italian Antonio Giovinazzi will stay with Alfa Romeo next season alongside Kimi Raikkonen, the Swiss-based Formula One team said on Monday.
The decision to stick with the 25-year-old rookie effectively ends any hope of German Nico Hulkenberg, who is leaving Renault, securing a race seat in 2020.
"Antonio has emerged as a very quick driver, even alongside as tough a benchmark as Kimi, and we expect him to develop even further as his experience grows," said team boss Frederic Vasseur in a statement.
"His technical feedback, work ethics and positive approach will help us continue to push our team forward, and so will the consistency of an unchanged line-up for next season."
Giovinazzi has scored four points from 19 races, compared to 31 for 2007 world champion Raikkonen.
"We learned a lot this year and I am confident we can make a big step forward next season. I won’t be a rookie anymore so there won’t be any excuses for me," said the only Italian driver on the starting grid.
Hulkenberg, 32, is being replaced by Frenchman Esteban Ocon at Renault next season and Alfa was one of just two teams left with a potential vacancy.
The other is Williams, for whom the German made his debut in 2010, but that team is expected to sign Canadian F2 driver Nicholas Latifi.
Williams have said they are not in talks with Hulkenberg, who has also recognised he is not a contender for that seat.
Hulkenberg holds the Formula One record for the most starts without ever standing on the podium, having finished fourth three times in his 175 races.