Lewis ended Friday in Austria on top as the Silver Arrows were quickest out of the blocks around the Spielberg circuit.
Lewis: 'Most importantly, the car feels fantastically fast here'
The Brit set a blistering pace in the opening session, clocking a 1:05.975s - the fastest ever lap of Spielberg - on the Soft tyre to end up three tenths clear of Verstappen's Red Bull in P2.
Lewis then went even quicker in the afternoon, following up his record-setting pace from the morning with a lap of 1:05.483s - 0.147s faster than Vettel's Ferrari.
"It's been a really good Friday with no major headaches to complain about so far," said the three-time champion. We had to swap out a spark plug during FP2, but the guys did a great job to turn the car around and we still managed to complete our programme.
"Most importantly, the car feels fantastically fast here. There's already a nice balance and it feels good out on track. This car is so quick in comparison to what we raced here last year. It's tricky, but a proper thrill to hook up a lap.
"The team is in good spirits and we're all up for another exciting fight with the Ferraris this weekend."
Valtteri: 'This track punishes you if you make a mistake'
Valtteri backed up Lewis' pace with a solid start of his own, going third fastest in both sessions on Friday and ending the day 0.216s shy of Lewis' pace-setting time.
"There's a good feeling inside the team and the car is clearly quick here," said Valtteri.
"It was great to see that the upgrades the team worked so hard to deliver for this weekend worked straight out of the box. Aerodynamically we've made another step forward from Baku, which is encouraging.
"This track punishes you if you make a mistake, and I tested those limits, but that's something I can learn from and build upon for the rest of the weekend. The balance of the car feels good and we'll fine tune the setup some more tonight to be ready for qualifying.
"Ferrari are looking strong here too, so we're expecting another interesting weekend ahead."
James: 'We showed good pace on both low and high fuel'
Friday was a positive start to the Austrian Grand Prix weekend and Technical Director James Allison is optimistic that there's still more to come from the Silver Arrows.
"We still have a few unanswered questions after today's practice sessions but it was nevertheless a pretty promising Friday," he said. "We ran all three tyre compounds and they were unusually close in performance at this circuit. But it was clear that our car was decently balanced on all of them.
"We showed good pace on both low and high fuel, although we have the feeling there is still a little more to be found at the lower fuel level. But it was a good start overall."