Sergio Perez was frustrated by a lack of progress with the tyres despite claiming fourth on the grid at the Portuguese Grand Prix.

In terms of Red Bull's expectations, the Mexican produced another strong result, finishing less than two-tenths behind teammate Max Verstappen and very much in the fight with Mercedes, who locked out the front row for the first time this season.

But Perez, like many drivers, admits he has been unable to find what works around Portimao in the RB16B.

"I didn't feel comfortable with the car at all," Checo said post-session. "I was unable to get the best out of my tyres so we've got some work to do to understand that.

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"I'm not very pleased with the progression I have had this weekend. I mainly did the same lap times as FP1. It's a very tricky track.

"When you do not have that confidence in Portimao, it's a big killer."

A combination of Pirelli's hardest compounds and a very smooth track means grip has been at a premium all weekend.

And Perez, who is usually one of the best at tyre management, explained the issues faced.

"This track is all about the tyres and getting them to the right temperature which is very difficult," he said.

"I tried everything in terms of warm-up with my out laps, build laps, push laps but nothing seemed to work.

"I think it's probably a step worse this year because we have less downforce on the cars and the tyres are probably a step worse than last year," he added.

"I mean, the lap times are crazy compared to last year, I think about a second lap slower. There's a big lack of grip.

"The conditions with the wind made it more tricky and they probably suited the Mercedes better but we still have a good starting position and a great opportunity tomorrow so anything can happen.

"I think it will be a tight battle around us so I’m looking forward to that. We just need to put the pressure on the Mercedes and hopefully we can fight for a podium."