Felipe Massa fears McLaren's F-duct system could make life complicated for the rest of the field in this weekend's Chinese Grand Prix, with the Woking squad set to have a crucial advantage on the Shanghai track's long back straight.
The straight between Turn 13 and the Turn 14 hairpin in China is one of the longest in Formula 1, and sees top speeds in excess of 300km/h.
The F-duct - which allows the team to increase its top speed by 'stalling' the rear wing on straights - helped McLaren set the practice pace at Sepang, which also features long straights, although the weather then disrupted the rest of the team's weekend.
Massa thinks Lewis Hamilton and Jenson Button's straightline speed will be a huge boost for them in China, and that rivals might have to compromise their set-ups to try and contain the McLarens on the straight.
"It's a nice circuit to drive and the extremely long straight leading into a tight corner means there is a real possibility to overtake," said Massa of the Shanghai circuit.
"However, we will need to be careful on that straight this year, because we have seen that the McLaren in particular has a very high top speed, so in case of a close battle with them we will have to be careful and ready to defend position."
Hamilton acknowledged that the length of the straight was good for McLaren's chances at Shanghai.
"Overtaking is possible at this circuit, particularly at the end of the long back straight, so I'm pretty confident we'll have another competitive weekend," he said.
Sauber has also now introduced an F-duct, and AUTOSPORT understands that Williams has a device in the advanced stages of development.
Ferrari is working on its own system too, but team boss Stefano Domenicali said in Malaysia that it would not rush the F-duct into use.
"For sure we are working flat out at home, because we saw the benefit that seems to be very, very big on the main straight in certain conditions - with the stalling of the rear wing," he said.
"We will bring it as soon as everything will be reliable, and we will be 100 per cent sure that the system works."
Massa is optimistic that the new parts Ferrari already has scheduled for introduction in China will keep it in the fight with McLaren and Red Bull.
"I'm also looking forward to the fact that we will have some new components on the car, aimed at improving performance and I hope they prove to be successful to help us in our fight, especially with the Red Bulls and the McLarens," he said.