Former F1 grand prix winner David Coulthard believes Mercedes made a mistake in not promoting George Russell from Williams during the summer break.
Russell was announced as Lewis Hamilton's team-mate for 2022 ahead of the Italian Grand Prix, replacing Alfa Romeo-bound Valtteri Bottas.
Since the decision was made, Bottas has seen an upturn of form, taking the fastest qualifying time and sprint win in Monza, as well as pole and the win in Turkey and then sprint victory in Brazil.
Despite this, when asked on Channel 4 if Mercedes had made a mistake in not making the switch in the summer break, Coulthard answered: "Arguably yes.
"George represents the future, they committed to him for next year.
"I think it was more a case of, look, Valtteri has got good speed, they have a loyalty towards him in that they signed a contract for this year.
"So I think that actually is about Mercedes honouring their contract rather than doing what probably would have been a real shot in the arm for them in terms of having a really motivated rear gunner.
"How motivated can Valtteri be when he knows he is leaving the team?"
Hamilton win "human performance at the highest level"
Hamilton took a sublime victory in São Paulo after starting Saturday's sprint last following his disqualification from qualifying after a DRS infringement.
The Briton made 15 places up in the 24-lap event before claiming the win from 10th on the grid after taking his overhanging five-place grid penalty for an ICE change.
"That is the thing that makes it so wonderful that we are here to witness this performance, this is human performance at the highest level," said Coulthard.
"This is someone who is not going to... 'I have an engine penalty, oh I have been disqualified' shoulders down and giving up, he goes 'okay, opportunity'.
"That is the thing I love about Lewis Hamilton - you cannot keep him down."