Heikki Kovalainen has admitted that he cannot quite understand McLaren team-mate Lewis Hamilton's decision to fit Bridgestone's 'intermediate' tyre at the start of phase two qualifying at Monza.

The pair had topped the opening stage of the knock-out session, albeit with Hamilton needing a late lap to vault into second, but, while the majority of the remaining runners continued with the 'extreme' wet tyre option as rain continued to come and go with varying intensity, the Briton used the break between sessions to fit the less-heavily treaded option.

It proved to be a disastrous tactical error for the championship leader, who simply could not generate the grip that he needed to post quicker times than his rivals and, by the time he had returned to the pits for the 'extreme' alternative, he had missed the window for quickest times as the rain returned. Unable to even match those immediately ahead of him on the timesheets in the worsening conditions, Hamilton had to make do with a career-low 15th place.

Kovalainen, meanwhile, went on to claim second spot in both the final two phases of qualifying, and will line up on the front row of the grid for the Italian Grand Prix, alongside first-time polewinner Sebastian Vettel.

"I honestly don't know exactly what was going on with Lewis and his engineer," the Finn admitted, clearly puzzled by his team-mate's decision, "I don't think inters were ever possible. Perhaps at the start of the second session, if it had not rained anymore, but, when we went out, I thought I had definitely made the right choice by taking the extreme wets.

"We decided to stay on the same set of tyres that we had in the first part of qualifying. It looked like it might start to rain later on, so it was important to do a lap at the beginning and, obviously, Lewis thought it would be dry enough for the intermediate tyres. Then it just started to rain as we went out...."

"In Q2, it was very difficult," polewinner Vettel agreed, "I set the time quite early. I was lucky to get a clean lap and I put it all together in this lap as, towards the end of the session, there was more and more rain, so the people waiting more and more to go out had a bit of bad luck. We never knew how the weather was going to be - the weather forecast changes every five to ten minutes, so it is quite difficult. In the end, I think, it was smarter to go out and have some running and not focus on getting one lap on the lightest fuel level possible."

"Looking back, I think the beginning of each session was crucial, especially the last two sessions," Kovalainen continued, "It was almost on the first two laps that you had to do the lap time otherwise the circuit was too wet, as the water level was increasing and the lap times were getting slower. Obviously, that's unlucky for Lewis, but I am sure he will do a strong race tomorrow."

Although overtaking is more possible at Monza than some other circuits on the schedule - something Hamilton proved in his first Italian Grand Prix a year ago - third-placed Mark Webber has questioned just how much ground the Briton, and 14th-placed Kimi Raikkonen, will be able to make up in the 53-lap race.

"I think they will have a chance to come through but, as usual, the further up you get, the harder it will become for them," the Australian surmised, "The top ten that I saw before the start of the session was a little bit mixed in terms of it not being quite a normal top group, if you like, because some of those guys weren't in there.

"There's going to be some differently paced cars in dry conditions in the race, for sure. But, as you say, getting inside someone here in a few places is not easy. Turn one is the obvious place to get the passing done and, if you get a good run out of Parabolica, those guys can do the damage in the first chicane."