Sebastian Vettel carried on where he left off in Australia by leading the way in practice for the Chinese Grand Prix.
Vettel cemented his pre-season status as the number one rival to Lewis Hamilton and his all-conquering Mercedes team with his and Ferrari's first victory in 18 months following their triumph at Melbourne's Albert Park a fortnight ago.
And the four-time champion was fastest at the Shanghai International Circuit on Saturday morning, with his team-mate Kimi Raikkonen fractionally slower in second and Hamilton only fourth.
Vettel's lap of one minute and 33.336 seconds - at a track which was set to play to Mercedes' strengths - sends out an ominous warning to Hamilton, who was some 0.543 sec further back and slower than has team-mate, Valtteri Bottas, too.
Hamilton, however, made a slight mistake on his fastest lap - running wide at the hairpin - to provide him with some hope that he will be able to match Vettel in qualifying later on Saturday.
Following Friday's weather farce, in which second practice was abandoned without one driver completing a single lap, blue skies ensured a frenetic one-hour session here as the cars roared back into life on a dry track.
And while Ferrari and Mercedes led the way, Fernando Alonso's prediction that his McLaren team would be in for a tough weekend here played true as he finished 17th of the 20 runners, 2.5 seconds adrift of Vettel's best time. Alonso's team-mate Stoffel Vandoorne was last but one in the order.
Felipe Massa posted the fifth best lap for Williams ahead of the Red Bull duo of Max Verstappen and Daniel Ricciardo while there was some encouragement for Briton's Jolyon Palmer.
Palmer endured a miserable weekend in Melbourne - crashing out in practice before qualifying last and then retiring from the race with a brake issue - but the Englishman finished ninth on Saturday, two places ahead of his Renault team-mate Nico Hulkenberg.