Mercedes' Toto Wolff has hailed Red Bull engine partner Honda for producing a more potent power unit than the reigning champion team for 2021.
Although Lewis Hamilton pipped Max Verstappen at the post in Bahrain, it was the Red Bull-Honda that dominated with pace throughout the season opening weekend.
Wolff gives much of the credit to Honda.
"We lose at high speed. We can clearly see that we have a deficit there," said the Mercedes team boss.
Wolff said he thinks Mercedes' biggest deficit is "energy recovery".
"They (Honda) did a great job," he said. "They delivered an extremely competitive power unit and we have to accept that as sportspeople."
The Austrian is not surprised that Honda has ramped up its efforts for its last official season in Formula 1 for now.
"Honda is a very proud company. I was convinced from the start that they would put everything into this engine for their last year," Wolff said.
"They haven't left one stone unturned or any resource left out in order to finish the job properly. I'm happy for them and it's a good motivation for us."
Even Honda's technical boss Toyoharu Tanabe is not denying that the Japanese manufacturer has played an ace with its 2021 engine.
"Everything has changed compared to last year," he told as-web.jp. "If we had such an engine then, we would have competed for the title.
"It's true that it has become more powerful than last year's Mercedes engine. We can see this not only in the race but also qualifying and practice."
Tanabe said Red Bull is also very happy with the 2021 Honda unit.
"Adrian Newey thanked us for our help in finalising the car," said the Japanese. "Obviously, the new power unit helped to improve the aerodynamic efficiency of the car as well."
