Ferrari left Mercedes and Red Bull trailing as Kimi Raikkonen led an utterly dominant one-two in the second practice session at the Bahrain GP.
Raikkonen's 1:29.817 on supersoft tyres was just 0.011 seconds faster than Sebastian Vettel - but ominously more than half a second clear of Valtteri Bottas in third as the Scuderia laid down an impressive marker for the weekend.
Bottas finished a tenth ahead of team-mate Lewis Hamilton, though both Mercedes drivers struggled for grip under the lights in the desert, failing to extract the expected performance from their tyres.
It leaves world champions Mercedes on the back foot ahead of a crucial qualifying day, especially after Lewis Hamilton was hit with a five-place grid penalty for a gearbox change.
Ferrari, winners of the first race of the season, were described as being in "complete control" by Sky F1's Paul di Resta.
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It was an encouraging, if not blistering return to track action for Max Verstappen at Red Bull - he failed to set a time in Practice One due to an electrical glitch - with the Dutchman fifth in P2 and just ahead of team-mate Daniel Ricciardo, who was fastest in that first session.
The Red Bull duo were almost a second off Raikkonen's benchmark over a single lap but were particularly strong on their race simulation runs at the end of the session.
"Verstappen's long run was the most consistent and the best on the tyres so they have real pace for Sunday at least," Mercedes team principal & CEO Toto Wolff told Sky F1.
The only smear on a near-perfect evening for Raikkonen was the sight of his Ferrari grinding to a halt towards the end of the session, but was that was due to a botched pitstop rather than a mechanical failure.
The error came on his front right tyre, and was a near carbon copy of Haas' issues from the season-opener in Australia, with Raikkonen forced to abandon his car on his out-lap.
Raikkonen though will not face a grid penalty after the stewards determined Ferrari had done everything they could to minimise the risk of the tyre coming off by telling the Finn to stop immediately. Ferrari were fined 5,000 euros.
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Finnish compatriot Bottas, however, may have a cause for concern after he appeared to block off Ricciardo during the Australian's flying lap - with race stewards expected to have a close look at the incident.
In another competitive midfield battle, Nico Hulkenberg finished best of the rest for Renault, while Pierre Gasly impressed for Toro Rosso in eighth in front of McLaren duo Fernando Alonso and Stoffel Vandoorne.
McLaren will take solace from the fact they finished ahead of both Haas cars, and just half a second off the Red Bulls.
It was another disappointing session for Williams, with Lance Stroll 17th while Sergey Sirotkin was a place back, and span off during the session.
Marcus Ericsson suffered a similar fate and found himself in the gravel, though Sauber team-mate Charles Leclerc was more steady and competitive in 16th.
Brendon Hartley propped up the field, disappointingly so given Gasly's performance in the sister Toro Rosso.