Championship leader Hamilton took control of the session at the end of his race with a second set of soft tires.
His 1: 04.838 were 0.144 seconds ahead of Vettel's best time after the Ferrari was out of sync compared to the remainder of the race. The front runners.
Valtteri Bottas was just 0.017 seconds behind Vettel in the second Mercedes, while Charles Leclerc finished in first four places as Ferrari went through the development elements to see why some of the upgrades introduced last weekend did not work as expected.  None of these four riders had passed the early Red Bull Ring race when Max Verstappen started his team's home race by setting the pace initially on middle tires.
He switched times with Hamilton before Leclerc moved to the top of the field heaps on a fresh set of medium-sized tires.
After that, he improved to 1: 04.999 failed make after a few bridging and complaints about the brakes further progress.
Bottas had a delayed start after Mercedes discovered an oil leak an hour before the start of the First World War.
That meant he completed the inaugural training with a old-spec engine.
Unable to improve, Hamilton took a lead after a series of laps that threatened to set a new best time, but never quite reached.
Vettel then joined with about 20 new middle tires at minutes before the end he jumped to second place. Verstappen slipped to fifth place, four tenths behind the pace. He seemed to be able to drive a faster time after posting the best mid-range of all, but did not improve his best.
Red Bull teammate Pierre Gasly was just over a tenth slower when he started his weekend in an encouraging manner.
] Carlos Sainz won the best-of-the-remainder fight in his McLaren with a new, redesigned Renault engine.
The Spaniard was only a tenth slower than Gasly and four-tenths ahead of the factory Renault of Daniel Ricciardo.
Kevin Magnussens Haas and Lando Norris' second McLaren finished in the top 10.
Slightly more than three minutes from time, the session was on the red flag.
Nico Hulkenberg ran out of the penultimate corner and broke the front wing on the yellow sausage edges that line the drain.
He returned over the grass at the last corner and broke more of his car, covering the track with wreckage.