"That was one of our worst days in racing," declared team boss Toto Wolff as seven-times world champion Lewis Hamilton finished fifth and George Russell seventh.

Red Bull's double world champion Max Verstappen led team mate Sergio Perez in a one-two finish with the Dutch driver finishing 50.977 seconds up the road from Hamilton.

"It was not good at all; we are lacking pace front, right, and centre," said Wolff.

"The Aston Martins are very fast, and the Red Bull is just on a different planet. It hurts that they are so far ahead," added the Austrian.

Red Bull ended Mercedes's run of eight successive constructors' titles last season and Wolff said the start to the 2023 season felt like being on the receiving end of the punishment his team once meted out to others.

"It reminds me of our best years where we put one second on everyone else. That is the benchmark. We need to put one foot in front of the other to come back but nobody in this team will throw in the towel," he said.

"We need to dig deep, deeper than we ever have done before. And we can do that."

Hamilton, whose hopes of a record eighth championship look like disappearing for the third year in a row, said Mercedes had done their best.

"We are the fourth fastest team right now, and the Ferrari and Aston that we were battling were just quicker than us," said the 38-year-old Briton.

"We know we are not where we need to be. I've got to stay positive, keep my head up and keep pushing the team. I will be a positive light for them and get the best points I can."

Trackside engineering director Andrew Shovlin said Mercedes lacked overall grip.