Tyre wear and performance was crucial in last week's season opener in Australia, where Red Bull had the fastest car on outright pace but was defeated by Lotus and Ferrari when it struggled with the Pirellis in the race.
Webber was fastest in the first session in Malaysia but said tyres were now such a dominant factor in performance that little else mattered.
"The whole category is geared around tyres at the moment," he said.
"Everything is around tyres. Tyres, tyres, tyre, tyres, tyres..."
After dry morning practice, the afternoon session featured a brief but heavy rain shower.
Webber described the damp track are "the only conditions [the slicks] work in, to be honest..."
The Australian's team-mate Sebastian Vettel said that tyre wear in Malaysia was another step worse than it had been in Australia.
Asked how he felt about potential race pace, Vettel replied: "It looked pretty OK but quite a mess if you look at how long the tyres last.
"It doesn't look very nice I would say. I hope we have enough tyres to survive the race.
"Today tyre wear was pretty severe for everyone, so obviously you go around way under the [potential of the] car.
"It is not a lot of fun and that is how it is."
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