Shanghai - Sebastian Vettel said Ferrari had much "homework" to do after a team orders controversy capped a disappointing weekend at the Chinese Grand Prix.
The Italian marque has shown superior straight-line speed this season, but Mercedes has taken first and second in all three races so far in a run that has surprised even championship leader Lewis Hamilton.
The reigning world champion seized control of the drivers' standings with victory ahead of team-mate Valtteri Bottas in Shanghai on Sunday, while Ferrari's challenge dissolved behind them.
Ferrari's Vettel was third but Charles Leclerc finished fifth after the 21-year-old rising star was controversially ordered to make way for his senior team-mate, a four-time world champion.
Vettel bristled at questions over the team orders to Leclerc, but much of his frustration will stem from Ferrari's continuing inability to get the best out of its car.
"In terms of calls from our pit wall today, the priority always lies within the team and Charles and I are both aware we are driving for the team," said Vettel, 31.
"We can do our own race but first of all we have to ensure Ferrari is in a position to fight with its rivals.
"I think we have a good car and we are still not able to unlock its potential completely."
Team principal Mattia Binotto made clear before the race that Vettel remained the priority over the talented but inexperienced Leclerc.
The plan was to put pressure on the Mercedes duo at the front, but Vettel failed to make inroads and Leclerc was caught by Red Bull's Max Verstappen who split the Ferraris to come fourth.
"Our decisions on strategy were taken to try to maximise the team's result," Binotto said, praising the way that the clearly unhappy Leclerc handled the situation.
Binotto feels that while Ferrari had the better package in Bahrain - where Hamilton only won because Leclerc's Ferrari lost power - Mercedes had the edge in Shanghai.
"Things are changing from one weekend to the next and therefore we need to look at the championship thinking that every race may be different," he said.
"We will go back to Maranello (Ferrari HQ) and look at all the data, try to understand what didn't work this weekend in order to improve," he added.
Vettel, who was hardly jubilant despite his first podium of 2019, put it more bluntly: "Plenty of homework for us."
Meanwhile Hamilton and his team principal Toto Wolff were baffled by Ferrari's failure to push them harder in Shanghai.
"I'm not really sure where they are losing out, but they're gaining something like 0.4 seconds on the straights but losing out on corners," said Hamilton, who feels that Mercedes are "over-delivering a little bit".
Wolff said: "Based on our long-run simulations we didn't think it would be so straightforward and our advantage to Ferrari came as a bit of a surprise."
But he also had a word of caution for the next race on the streets of the capital of Azerbaijan in two weeks.
"Baku is a different ball-game, there's a very long straight and we need to get the power and drag level there right," warned Wolff.