Whilst the displaced Carlos Sainz was initially tipped for the drive, a new candidate soon emerged as Mercedes’ top choice - their junior driver Kimi Antonelli.
The Italian F4 and Formula Regional European champion, achieved two impressive F2 wins, and after taking part in a series of tests for the team secured the coveted seat alongside George Russell.
Have Mercedes made the right Kimi Antonelli decision?
The 18-year-old made his F1 debut at Monza, where he featured in his first FP1 session with Mercedes, but despite setting blistering pace at the start, Antonelli crashed into the barriers, ending his run prematurely.
Mercedes boss Toto Wolff remained supportive of the youngster after the mistake, but has since revealed that the team made an error by allowing him to take part in the session.
“I wouldn't say it was a mistake, but I think we weren't completely right in assessing the pressures that he could find himself under,” Wolff said to Autosport.
“Why that is, is that we talked about it, and how to approach the session. He has been brilliant in testing. He has never put a single foot wrong in the many thousands of kilometres that he's done.
“But it's a different ball game if you're an Italian driver, you're 18 years old in Monza and it’s your first opportunity.
“Maybe if we had considered that as a risk factor against the set of data we had from him, probably it would have been wise to give him an FP1 that would have been in a totally different time zone than Italy. But he will learn a lot from that.”