Sergio Perez was at a loss to explain why Pirelli's soft tyre failed to produce any lap time gains on Friday at Portimão, where the Red Bull driver concluded his day well adrift from teammate Max Verstappen.
Perez felt his pace on the medium tyre was good but the switch to the red-walled soft compound that will be used in qualifying was of little benefit and left the Mexican over half a second behind Verstappen who also had a grip with Pirelli's softs.
"Today we had very similar track surface conditions to last year with limited grip on the new tarmac so it’s really hard to get the tyres to work," Perez said after Friday's running.
"It’s not easy so the main focus is to understand what’s going on with the tyres.
"I think the pace on the mediums was good but when we went on to the soft compound we didn’t find any lap time so we’ll need to look into that and hopefully sort it out in time for qualifying."
Perez, who qualified on the front row alongside Lewis Hamilton last time out at Imola, believes the inherent level of performance of Red Bull's RB16B should allow him to challenge for pole once again on Saturday.
"It’s hard to compare with the last round in Imola as it’s a very different track here and everywhere just has less grip overall due to the tarmac, but I think we have pretty good pace in the car so hopefully we will be in the mix to fight for pole tomorrow," he concluded.
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