Lewis Hamilton has admitted that he will struggle to hang on to his new lead in the 2018 world championship.
Hamilton's first win of the season in Baku puts him four points ahead of Sebastian Vettel, but he admits that it is the Ferrari with the fastest car.
"Leading the championship is great, but if we continue as we are, it will take a lot of lucky races to keep me here," the Mercedes driver is quoted as saying by Marca.
"And you can't expect that for the next 17 races."
The Briton said that the biggest problem with the 2018 car is the tyres, but admitted that he also needs to improve on a personal level.
"The car has the pace but we are not unlocking it. We need performance and I need a rhythm and they're not in perfect harmony," he explained.
As for Ferrari, Hamilton admitted: "Their pure pace is much better than ours at the moment.
"By no means do we have a bad car, but we need to improve it to make it easier to drive.
"I felt really good in Australia but it hasn't worked out since then and I'm not sure why."
Liberty Media's sporting boss Ross Brawn agrees with Hamilton that Ferrari is ahead of Mercedes after four races.
"It is the first time since the beginning of the hybrid era that Mercedes is not technically superior to its opponents," he is quoted as saying by Globo.
The championship continues with the Spanish Grand Prix next weekend.