Having finished second in the Hungarian GP, Lotus's rivals admit they are wary of the challenging being posed by Kimi Raikkonen and his team.
Raikkonen missed out on Sunday's victory by a mere second but took some consolation from his fifth podium finish of the season.
The 2007 World Champion, who is in his comeback season with Lotus after two years away from the sport, is currently fifth in the Drivers' Championship, just 48 points behind Fernando Alonso with nine races remaining.
"I was not surprised by Kimi because I have always thought Kimi is a very good driver and a World Champion - which you don't do unless you have something special," said Ferrari team boss Stefano Domenicali.
"I think that Lotus didn't collect the points that they were able to collect. They have had a good car since the beginning, so they could have more points.
"They seem to be very gentle on the tyres too, and they will be a very good team in the second half of the season."
However, the Italian team is not the only outfit wary of the Lotus threat.
"Their car has been quick all year, and they have two good drivers, so Kimi is a factor in the Drivers' Championship," said Red Bull's Christian Horner.
"He is only one point behind Lewis (Hamilton), so it would be foolish to underestimate any of our rivals at the moment and there is still a long way to go."
Meanwhile, McLaren's sporting director Sam Michael added: "Yeah they are fast, but worrying about them doesn't do anything. You have to make the car faster."
