Mercedes driver Hamilton endured a frustrating weekend in Jeddah, qualifying eighth and then finishing ninth after a gamble to stay out and gain track position under the safety car failed to pay off.
The track layout highlighted the car's below-par performance in fast corners, as Hamilton and his team-mate George Russell were both outpaced by at least one car from Red Bull, Ferrari, McLaren and Aston Martin, effectively benchmarking Mercedes as fifth fastest.
Team boss Toto Wolff admitted there was a "fundamental" issue with the car that meant it struggled on high-speed corners.
Hamilton suggested that it may take some time to improve the W15, and thus there could be some difficult weekends ahead.
"It's going to be challenging in these next races," he said. "I think all the high-speed circuits we are going to be at a disadvantage with the package we currently have.
"But we're good in the low-speed, and some of the medium-speed, we're not so bad. It's just really the high-speed, so we just have to add performance."
He added: "It was like I was in a different category when I was going through the high speed with the other guys around me."
In Jeddah, Hamilton had a battle with McLaren's Oscar Piastri that lasted for many laps, and while he enjoyed being able to race he admitted that he couldn't take much pleasure from the overall result.
Source: Autosport