Kimi Raikkonen believes ERS is holding Ferrari F1 team back

The Scuderia has struggled for straightline speed all season and suffered a disastrous home grand prix in Italy recently, where it failed to qualify inside the top six and recorded a best result of ninth with Raikkonen.

Fernando Alonso's ERS failed at Monza, causing his first mechanical retirement as a Ferrari driver since 2010, while Raikkonen struggled to make progress from 11th place on the grid.

The Finn also found wheel-to-wheel battle difficult during the previous race in Belgium, and said energy recovery and deployment was a particular weakness of the F14 T compared to the Mercedes-engined cars and the Red Bull-Renaults.

"I think in the race conditions it's one point that we have to look at," said Raikkonen, when asked by AUTOSPORT if a weak ERS was why Ferrari struggled for straightline speed in races.

"But during the season it's not so easy [because of the engine freeze].

"I'm sure we can make a 100 per cent improvement over the winter.

"We have made some improvements already and I think if you look at certain engine manufacturers [compared to us] over one lap it's not too bad, but then in a race distance we seem to be struggling a bit in certain places."

Raikkonen said he expected upcoming races on more twisty circuits than Spa and Monza to suit Ferrari's F14 T better.

When asked whether he expected stronger form from Ferrari during the next race in Singapore, Raikkonen said: "It's hard to say as it's a different year and different car [for me].

"We expected [Monza] to be difficult, but I think the next few circuits will suit us as they're not so fast.

"We have to go there and see how the car is, but I expect to be in a stronger position."