Lewis Hamilton described his Saudi Arabian Grand Prix as "horrible" and said he had no explanation for his lack of pace in the Ferrari.
The seven-time champion finished seventh and was 31 seconds behind team-mate Charles Leclerc, who scored Ferrari's first grand prix podium of the season with third place.
"Nothing positive to take from today," Hamilton said, "apart from Charles on the podium, which is great for the team.
"It was horrible, not enjoyable at all. I was just sliding around. It's pretty bad."
He is seventh in the drivers' championship with his best result in a full grand prix this season his fifth place in Bahrain a week ago.