Ferrari team chief Stefano Domenicali believes Lewis Hamilton and Kimi Raikkonen are now a major threat to Fernando Alonso's hopes of winning a third world championship.
Although Spaniard Alonso of Ferrari extended his lead in the drivers' title race after finishing third in Sunday's Italian Grand Prix, Domenicali admitted he was wary of the threat posed by both drivers.
Briton Hamilton, champion in 2008, secured McLaren's third win on the bounce moving him to second in the standings, while Finn Raikkonen of Lotus finished fifth bumping him up to third.
That meant Hamilton is now just 37 points behind Alonso in the drivers' title race with Raikkkonen just one point further adrift despite having not won a race.
"I have to respect all of them," said Domenicali, "I always said Kimi step-by-step is a dangerous driver, and he is getting closer and closer.
"Hamilton, with the car he has now, is very, very strong and we have seen in the last few races that anything can happen. So all the drivers that are in the top five/six I think need to be taken very seriously.
"We need to see race-by-race what is the competitive situation of the car that they are driving. That is the only thing we have to do now."
The Italian also believes the race for the constructor's championship is now much closer after both Germany's Sebastian Vettel and Australian Mark Webber retired leaving Red Bull pointless at Monza.
The Milton Keynes-based team hold just a 29-point lead over nearest rivals McLaren, with third-placed Ferrari a further 17 points afield.
Domenicali added: "I have to say for us that because of the retirement of Red Bull, the constructors' is difficult but still open for the four top teams.
"So it is another motivating factor for all of us, to make sure we are performing as we can and that is what we will do."