Valtteri Bottas took on a completely new power unit ahead of Friday qualifying for the Italian Grand Prix, and Mercedes Team Principal Toto Wolff admits the move wasn't simply a strategic one.
Earlier in the day, Wolff indicated that Mercedes were considering taking engine penalties at Monza, with the team ultimately deciding to give Bottas a fourth engine of the season.
The move allows Bottas to start Saturday's Sprint Qualifying from the front, as the grid penalty will only apply to the Grand Prix itself, but Wolff revealed that the decision was made due to some concerns over the power unit.
"We had a little bit of a worry. We wouldn't have taken it otherwise," Wolff told Sky Sports following Friday's qualifying session.
"With the Sprint format, it's quite good, because you only have to take the penalty on Sunday."
Mercedes have the advantage heading into Saturday's Sprint Qualifying, with Lewis Hamilton starting alongside Bottas on the front row, while Red Bull's Max Verstappen will line up behind them in third.
The Dutchman finished four-tenths slower than Bottas in qualifying, halving the deficit Red Bull had at the same track last season.
"It depends if you see the world with the glass half full or half empty. We're more half empty," Wolff stated when asked if he was pleased with the margin.
"It's a solid advantage, I think we can be happy about that, but I think that the critical part is trying to perform every single weekend and not have any DNFs."
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