Carlos Sainz says high tyre degradation is costing Ferrari in their battle with rivals Mercedes and Aston Martin.
The Scuderia were expected to start the season as Red Bull's closest challengers, but have been beset by a combination of poor race pace and reliability problems which mean they have finished off the podium in both of the opening two rounds of the campaign, and are fourth in the constructors' standings.
In Jeddah on Sunday Sainz could only bring the SF23 home in sixth place, one spot ahead of team-mate Charles Leclerc, having been unable to keep pace with the faster Aston Martin and Mercedes cars ahead.
The 28-year-old says that the Ferrari is harder on its tyres than the competition.
"The last stint [on the hard tyres] proves that we are not where we would like to be,” Sainz told the media post-race. "We have more degradation than the Mercedes and the Aston Martins and we lack rhythm.
"I'm a bit surprised because after Friday I thought we had a chance to be the second fastest [car]. This hard tyre stint shows that we still have a lot of work to do."
Sainz lost one spot on the opening lap to Lance Stroll, before regaining the place later with an overcut strategy after extending his first stint on the medium Pirelli rubber. When the Canadian retired due to a mechanical failure a few laps later, Sainz's progress was curtailed and he was unable to hold onto Lewis Hamilton ahead.
"[The safety car] wasn't the best timing," Sainz conceded. "We got the overcut on Stroll and we were starting to get a bit more pace after suffering in the dirty air behind him but honestly the result wouldn't have changed much [without the safety car]."