LONDON (Dispatches) - Mercedes say they face a difficult task stopping Ferrari's Sebastian Vettel retaking the championship lead in Singapore on Sunday.
Mercedes driver Lewis Hamilton moved ahead of the German for the first time this season with victory in Italy.
The Briton leads Vettel by three points as they head to the slow and twisty Marina Bay track this weekend.
Team boss Toto Wolff said: "It is a circuit that we have found difficult to master"
He added: "We head to Asia with the expectation that we have a big challenge ahead of us."
Mercedes were beaten by Ferrari in Singapore in 2015, when they had their least competitive weekend of an otherwise dominant year, and were run closer there last season by Red Bull and Ferrari than at virtually any other track.
The Ferrari has proved much more competitive than the Mercedes on slow tracks in hot climates - they took one-twos in both Monaco and Hungary.
Hamilton said after his back-to-back wins in Belgium and Italy: "The learning from these two weeks should collectively put us in a better position for Singapore but I think still Ferrari are going to be quick there. They are rapid through the medium and low-speed sections of circuits.
*****Sebastian Vettel is three points behind leader Lewis Hamilton