Istanbul: Jenson Button believes the outcome of this weekend's Turkish Grand Prix will be a solid indicator of which teams have the fastest cars for the rest of this year's Formula One world championship.
The 2009 champion, who topped the times for McLaren in opening free practice on Friday, said he felt that it was this race weekend that showed him last year where his team stood in relation to pace-setters Red Bull for the rest of the season.
He said that he did not think that Red Bull were in a league of their own after winning two of the season opening trio of flyaway Grands Prix in Australia, Malaysia and China.
Button said: "I don't know exactly where we are now. We will have to wait until Sunday to see, but I think in China we were very close to them and possibly closer in the race.
"Qualifying we are further away, and it is a massive gap, but that doesn't win you a race. I think we are closer in race trim. I can tell you a lot more after this race because this is the GP last year that we picked up pace and were actually able to race them."
He added that he did not think any of the many upgrades introduced this weekend would make a substantial change to the order at the top of the field.
"Everyone has upgrades and it is about whose upgrades work and whose are big," he said.
"You hear rumours that Red Bulls' is a big upgrade and Ferraris is big, and that Mercedes' is not as big and may be ours isn't as big."
"But I wouldn't say we could bring an upgrade that is seven and a half tenths and Red Bull stands still. So I think they will be very quick in qualifying."
"I am sure they are thinking, we would rather take away some of our qualifying performance and put it in our race car. I am sure they are happy in qualifying but I am sure they would rather be quicker in the race."
After being beaten by defending champion Sebastian Vettel of Red Bull in the first two races, McLaren bounced back to win with Lewis Hamilton, the 2008 champion, in China.