Max Verstappen is braced for a difficult Monaco Grand Prix weekend aware that his rivals are beginning to mount a sustained challenge to his bid for a fourth consecutive drivers' world title. The three-time champion and series leader said on Thursday that he felt both Ferrari and McLaren could threaten his hopes of a third victory in the Mediterranean principality in Sunday's race. "It's one of the more difficult tracks for us," said the 26-year-old Dutchman, who won last Sunday's Emilia Romagna Grand Prix by less than a second ahead of McLaren's Lando Norris. "In the last few years, Ferrari have always been very, very strong here and McLaren, lately, in the last two races, have really ramped up their performance so they are, for sure, ones to watch as well.