Lewis Hamilton set the pace in first practice for the Austrian GP on Friday morning ahead of Max Verstappen and Valtteri Bottas.
Hamilton produced a lap of 1:05.975 to top the charts ahead of his Mercedes team-mate by almost half a second but only two tenths clear of Verstappen.
Ominously for the rest of the field, Hamilton's fastest lap was set on soft tyres - the slowest of the three compounds Pirelli have brought to Austria this weekend.
World championship leader Sebastian Vettel was only fourth fastest with Verstappen's speed on the same type of tyre - the supersofts - further suggestion that Red Bull have caught the Ferraris after the Scuderia's momentum was apparently punctured by the FIA's crackdown on oil burning.
Ironically, the characteristics of the Red Bull Ring does not suit their hosts but Verstappen's fast start was an encouraging beginning for the former world champions.
"This is a very power-sensitive circuit in sectors one and three so hopefully we're not flattering to deceive at the moment," admitted team boss Christian Horner. "We keep asking Dietrich [Mateschitz, the Red Bull owner] to put in more corners, but they haven't arrived yet!"
It's expected that later this weekend Vettel will revert to the engine he was set to use in Baku before a hydraulics fault necessitated a precautionary change ahead of qualifying.
Both McLarens also finished in the top 10 with Stoffel Vandoorne a season-best seventh.
But while the team have been boosted by the introduction of an upgraded engine from Honda, their performance on Friday morning was inflated by the use of the ultrasoft tyres. Fernando Alonso was ninth.
A number of drivers struggled for grip during the session with both Ferraris spinning within the opening half-hour of action.
Valtteri Bottas, running immediately behind Raikkonen, also spun into the tricky first corner towards the end of the session. Hamilton wasn't immune either, running wide at both Turn One and Turn Three on his final run with Verstappen also going wide in the final minutes when on a lap which had been on course to challenge Hamilton's benchmark.
Practice Two starts at 1pm UK time.
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