Max Verstappen has suggested that Mercedes might have an advantage on the softer range of tyres that have been made available by Pirelli this weekend for the Austrian Grand Prix.
Verstappen was quickest in first practice, but slipped to third place behind Lewis Hamilton and Valtteri Bottas in the afternoon.
"From our side the run on the soft tyre was not perfect," he said in comments to the media after the end of Friday's sessions. "Nevertheless I felt good in the car, and everything feels pretty good.
"There are no real issues so we just need to make sure we find some more speed on the softs," he commented. "Mercedes looked quite quick on the soft so we just have to make sure we have a little more pace on that compound."
"I think we are looking good on the mediums, and also in the long runs it is looking good," he said. "That's the most important thing in the end.
"The most important thing is to make sure the softer compounds hold up during the race, that will be a challenge."
Verstappen's comments were echoed by those of Red Bull motorsports consultant r Helmut Marko.
Mercedes definitely showed themselves a bit more," he told ServusTV. "We didn't handle the softs as well as we had imagined. We didn't have the optimum grip. But we know what the problem is."
Even if this proves to be the case for the rest of the weekend, Marko is confident that Red Bull will be able to more than match their rivals on the medium and hard compound which are likely to be the crucial compounds for qualifying and the race.
"If you look at the top speed, you can assume that Mercedes have upped the engine a notch," he said. "[But] the long-run on the mediums were very good for us.
"That was very good," the 78-yer-old added, predicting that the medium will be the optimal compound for Sunday's race. "For us, there is no alternative as a race tyre."
Marko was even optimistic about the team's chances if Sunday proves to be wet, after Verstappen adapted well to Friday's afternoon drizzle. "Max in particular immediately showed again how good he is, and that's also where the set-up we have is absolutely good, even for slightly wet conditions."
Verstappen himself was looking forward to the challenge of going for back-to-back victories at the Red Bull Ring. "It will be exciting, Mercedes has become stronger, we will see during qualifying tomorrow," he said.
"It did get quite greasy out there but luckily it was good enough to keep on driving so we had a good read on the long run pace.
"I think it will be tight again this weekend as it looks like Mercedes improved a bit but we will see tomorrow in qualifying."
Verstappen's team mate Sergio Perez admitted that he had been off the pace on Friday, finishing FP2 in 11th place almost a full second slower than Hamilton.
"There’s still a lot of work to do," the Mexican driver acknowledged. "Both sessions were quite tough and I’m not feeling fully comfortable with the car on the softer compound yet.
"We need to analyse the data tonight to try and get the pace back to where we would expect it to be, ready for qualifying tomorrow. We seemed to be quite far away from the balance with the low fuel but we corrected that quite quickly.
"We were also seeing less degradation on these tyres too, which is good," he added. "Overall I learnt a lot from today.
"Hopefully we can have a good qualifying tomorrow and a solid race on Sunday.”