Sebastian Vettel won the Singapore Grand Prix from his Ferrari team-mate Charles Leclerc while Lewis Hamilton could only manage fourth.
And the Mercedes driver has admitted his team need to step it up if they are going to be successful.
Hamilton currently leads his team-mate Valtteri Bottas by 55 points with just six races remaining.
But the Brit is adamant Ferrari could still overturn his lead.
That’s because the Italian team have won the last three races with Leclerc victorious twice and Vettel once.
He said: “Clearly their [Ferrari’s] car works really well everywhere now so it’s going to be hard to beat them.
“They are so quick on the straights. We can’t compete with them on the straights.
“We’ve just got to stop dragging our feet.
“We’ve just got to re-huddle, get back together, work hard and move forwards.
“We were doing such a great job at the beginning of the year and we have this gap but this gap can easily go.
“I’m under no illusions, my gap in the championship — it’s not won yet. We’ve got to step it up.”
Sebastian Vettel controversially beat Leclerc in Singapore as he undercut his Ferrari team-mate.
After the race Leclerc said: “Obviously it is always difficult to lose a win like that but at the end it’s a one-two for the team so I’m happy for that, our first of the season.
“I’m disappointed for me but I will come back stronger.
“It looks a lot more positive than expected, they’ve [the mechanics] done an amazing job.”
F1 returns this weekend with the Russian Grand Prix in Sochi.