Lewis Hamilton has downplayed his blistering pace from Barcelona on Saturday insisting it is not indicative of things to come.
Arriving at the Circuit de Catalunya on Saturday, the best time so far this year was a 1:21.848 which had been set by McLaren's Sergio Perez last Wednesday.
Hamilton, though, blitzed his replacement's time on Saturday.
Putting in a five-lap run on the soft Pirelli tyres, the Mercedes driver clocked a 1:20.558.
The Brit, however, told James Allen On F1 that "there is no reason to be impressed.
"We came through all the tests and all the programmes we wanted to do and obviously our upgrade has been a positive, it was a small step forward for us.
"This is a good track to test on and give you a rough idea; if your car is good here then it should be good anywhere.
"If you look at the (Mercedes) car last year it was quick in Monaco so it should be competitive on the street circuits. When it comes to the downforce circuits it could be quite tough there."
He added: "The most important thing is that single lap pace can be easily achieved, it's long run pace that is the tough one."