Red Bull advisor Helmut Marko is still confident that Mercedes will have to change Lewis Hamilton's engine again before the end of the 2021 season.
There has been much speculation over whether the Briton will need a fifth engine of the campaign at some stage during the remaining five races.
Such a move could have a significant effect on the title battle, given that any change will result in a grid penalty, putting the driver towards the back of the field.
Hamilton already took a new Internal Combustion Engine at the Turkish Grand Prix. However, with this being only one part of the power unit, the penalty was a 10-place grid drop, rather than being moved to the back.
Nonetheless, Marko believes that the seven-time World Champion will have to fit another new engine at some point during the title run-in.
"We remain convinced that Hamilton needs a new engine," the Austrian told Gazzetta dello Sport.
As well as this possibility playing into Red Bull's favour, Marko thinks that the team may be at an advantage in terms of adapting better to the weather conditions at several upcoming Grands Prix.
"We are going to races where it is hot and in the past that has given us an advantage," he added.
Whilst Hamilton is yet to incur another engine penalty, his Mercedes teammate Valtteri Bottas has taken grid drops in three of the last four races.
No more engine changes at Red Bull
In the Red Bull camp, both Max Verstappen and Sergio Perez have faced grid penalties in 2021 after taking a new engine, but Marko does not expect either driver to have to do the same again.
"Under normal circumstances, we will not need to change engines," Marko said.
Verstappen heads into the next race of the season, the Mexican Grand Prix, as championship leader with a 12-point advantage over Hamilton.
Meanwhile, Red Bull trail Mercedes in the Constructors' Championship by 23 points.
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