Sebastian Vettel does not think McLaren has stolen a march on its rivals at recent races and says the top teams' form is still as difficult to predict as it was earlier in the season.

15908 - No car looks quickest - Vettel

Championship leader Fernando Alonso singled out McLaren as his stiffest competition on Friday after Lewis Hamilton and Jenson Button won the last two races on very different tracks. However, Vettel does not agree that one car is starting to have a clear lead and expects another close weekend at Monza.

"This year it's difficult to name the car," he said. "It depends very much which race we are talking about. I think the bottom line is that the cars are very close to each other and it's difficult to know before the weekend which is going to win. It's not just one or two teams, last weekend we had two Saubers in the first two rows, unfortunately they didn't make it past turn one, but I think the speed was there for them and it could be the same here. There are no ++++ cars this year and no cars that stand out."

He added: "We were very competitive here [at Monza] last year, not so much the previous years, so it's very difficult to know what to expect."

Vettel came second at the Belgian Grand Prix last weekend after failing to make the top-ten shootout in qualifying. Arriving at Monza four days later, he said there had not been enough time to figure out why he was lacking qualifying pace at Spa.

"Qualifying was disappointing but Sunday afternoon was okay and just before qualifying on Saturday morning it was okay," he said. "There is not a 100% bullet proof answer; there was nothing wrong with our qualifying and we didn't feel as though there was an awful lot more. So it's still a bit of a question mark."