Lewis Hamilton has conceded that Mercedes are now the "fourth best car" after the team finished 50 seconds off Max Verstappen during the Bahrain Grand Prix.
Mercedes has been struggling with tyre degradation for most of the weekend on the abrasive Bahrain track surface, with Hamilton coming into the race saying the team was in the dark on their race runs.
Despite getting a good start, he was unable to match the pace of Fernando Alonso in the Aston Martin and both Ferrari drivers.
"The the Ferrari's were just quicker than us today, we're the fourth fastest team. We was close for a second and then just couldn't hold on to him," he told media, including RacingNews365.com.
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Hamilton not confident about strategy
Prior to the race Hamilton discussed the strategy with his team, pointing out to his engineers that the car was not going to go as long on the stints as they predicted.
"When we did the strategy in the morning, I told the guys it wasn't going to go as far as they said it was going to go - and it didn't!" he said.
After Toto Wolff admitted that the team needs to change its car concept to challenge back up front, the seven-time World Champion says the team has a "lot of work to do" to add downforce to the car.
"We've got a lot of work to do. We've just got to add downforce to the car [because] we're lacking a lot of downforce.
"As soon as we put more load on the rear and the front and we'll pick up that pace."
Hamilton also made reference to the shared resources between Mercedes and Aston Martin, given the contrast in performance between the two teams.
"Hats off to the Aston Martin team, they did such an amazing job. We've got work to do, because half the car is ours!
"They build their car in our wind tunnel - or do their aero in our wind tunnel - so we've got some work to do."