Button says "massive degradation" spoiling long-run pace

The McLaren driver ended Friday 16th on the timesheets, two seconds behind pacesetter Nico Rosberg, while teammate Fernando Alonso was eighth, albeit still 1.7s slower than the Mercedes driver.

While admitting his best lap was compromised by errors, Button said he was confident of being able to reach the top 10 in qualifying, but said that his race runs were being spoiled by severe tyre wear.

"Over one lap there's everything to play for," said the 36-year-old, who is potentially racing at Suzuka for the final time in F1 machinery this weekend.

"It wasn't a good lap of mine, I had a lot of front locking, but it's only practice and tomorrow I think we can be more competitive, fight for the top 10.

"The race has been a big issue, the long-distance runs. We have to look at why that is, there's got to be something that's just not working with the car.

"We're looking at the data now and I think we'll change a lot of stuff because we have a massive degradation issue, which normally is a strength of mine.

"After one lap, the degradation is massive. We need to look at why that is and hopefully we can resolve it by tomorrow."

Button admitted Alonso was running a slightly different specification of car compared to his on Friday, but said he didn't think this accounted for the pace deficit.

"He [Alonso] has got some slightly different bits on the car than I have," Button added. "Even so, we should be more competitive on the longer runs because we're a long way off most people.

"I think it's something that's wrong with the car rather than a set-up issue."