Ferrari's progress against Mercedes will be 'limited' until 2016

Ferrari secured its third win and first double podium of the season in Singapore, but normal service resumed in Japan last weekend as Lewis Hamilton and Nico Rosberg gave Mercedes a one-two.

The Scuderia was second best, with Sebastian Vettel taking the final spot on the podium and Raikkonen recovering from sixth after an "average" lap in qualifying to finish fourth.

With all teams now focusing more heavily on 2016 development, Raikkonen admitted Ferrari's pursuit of Mercedes this term will be hampered.

"We know where the weaknesses are but there are limited things we can do at this time of year," said Raikkonen.

"Sure we'll keep improving and next year we'll be in a better shape.

"We're second best. We keep doing progress, we're doing the right things and we must keep improving."

Suzuka was the first true high downforce track since Silverstone in July and Raikkonen said the result showed how much progress the team has made.

"I don't think this [Suzuka] is exactly what fits us the best right now, but it's similar to Silverstone," he said.

"We were quite competitive, quite happy in the end.

"Certain circuits are slightly more tricky depending on the layout.

"It shouldn't be our favourite place, but it shows we are doing the right things."

ARRIVABENE: FERRARI STILL GAINING

Team principal Maurizio Arrivabene agreed Suzuka showed Ferrari had actually gained ground on Mercedes, despite being defeated.

"When you are not winning, of course you are disappointed. This is normal," he said.

"But the right comparison is not with Singapore, it's with Silverstone.

"If you look at the gap we had to Mercedes at Silverstone and the gap at Suzuka, it's smaller.

"And as I've said many times, certain tracks like Suzuka are not tracks that are good for our car.

"Of course after Monza [where Ferrari introduced an upgraded power unit], the engine helps a lot, but as you know the car is more or less the same.

"So I'm very proud of the work of all our engineers, of all our team, and in particular the engine department."

Third place means Vettel has now fallen 59 points behind Hamilton, with only 125 remaining from the final five grands prix.

Asked aout Vettel's title hopes, Arrivabene said: "It's like asking about winning the lottery and becoming a millionaire.

"To win the lottery you need to be lucky, so if we are lucky, yes! But we need to be really lucky."