McLaren will analyse the data before making a decision on whether to run the F-duct for Saturday's qualifying session.

BBC: Jenson Button 'needs' podium finish at Italian GP

He says: 'The two major technologies - the F-duct and the blown diffuser - we are still not completely there with.

BBC: Hungarian GP as it happened

Fernando Alonso reports the Ferrari feels more competitive without the F-duct and the team, like Red Bull, have canned the aerodynamic device.

BBC: Hungarian GP qualifying as it happened

Second practice then saw Hamilton abandon the F-duct, which increases speed on the straights, while Button completed the session with the aerodynamic aid in place.

BBC: Jenson Button 'needs' podium finish at Italian GP

It is made more complicated this year by the presence on many cars of the F-duct aerodynamic device, pioneered by McLaren but since adopted by several other teams.

BBC: Sebastian Vettel heads Ferrari pair in Monza practice

The F-duct normally improves straight-line speed but at Monza it is helping to improve cornering speed while the flatter, Monza-spec wing actually makes the car quicker on the straights.

BBC: Italian GP qualifying as it happened

"If you don't have aerodynamic features - like the F-duct or the exhaust blown diffuser - then you want to implement them, so you develop them at home, build them on to the car and test them on the race weekend, " explained Schumacher, who was used to unlimited testing in his previous Formula 1 career.

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