Charles Leclerc bemoaned a suspected power unit issue through qualifying he hopes will be diagnosed ahead of the 18-lap sprint for the Italian Grand Prix.
The Ferrari driver complained of an issue with engine braking from the start at Monza and after clearing Q1, his team set to work on a remedy.
Leclerc, however, fed back to the team the issue was worse as it had become inconsistent through corners, making the car even more difficult to drive.
The Monégasque was still able to finish eighth despite the issues and only 0.048secs behind team-mate Carlos Sainz.
"Today for me was a difficult day," said Leclerc. "We had an issue in qualifying, during the whole of qualifying. I don't know what it was but it was very difficult to drive.
"I won't go too much into details but it is something on the power unit that was happening.
"We are looking into it for tomorrow and fully fixing it otherwise it could be difficult to do the race like this.
"Overall, it is not that bad because we came P8 with this. It is a good result today."
Ferrari "kept improving" despite lack of pace
With a lack of engine power lingering from the Scuderia's difficult 2020 season, Monza was always going to be a weaker circuit for the team in the fight over third in the constructors' standings with McLaren.
Sainz was complimentary of the team's efforts to keep improving in front of the adoring Tifosi at the 'Temple of Speed'.
"It was a smooth quali the whole way through," explained Sainz.
"Unfortunately, since the beginning of Q1, we saw we were a bit too far away from the top five and that unfortunately, on a track like this where we want to do so well in front of the Tifosi, we are going to struggle to be in the top five.
"But we managed to keep improving throughout the session, we managed to put together some good laps, very close to each other.
"[We are] there or thereabouts so it shows the car is pretty much where it is. We want more for the future but that is what we had."