The German completed 77 laps on the final day of pre-season testing in Bahrain, the most a Red Bull has managed on a single day, but an attempt to complete a race distance failed.
He set the ninth fastest time of the final day of running, 4.190s off pacesetter Lewis Hamilton's best time of the day, but despite being concerned about speed he also believes that Red Bull has bigger problems to solve.
"Yeah, we are; it's not a secret," said Vettel when asked if he was concerned about Red Bull's laptimes.
"We cannot do the times that the guys at the top are doing for a couple of reasons, but at the moment we have bigger problems to solve than just the pace."
With only 11 days between the end of winter testing and the start of free practice for the season-opening Australian Grand Prix, Vettel accepts that Red Bull is playing catch-up.
Lewis Hamilton and Mercedes end winter on top
But he is hopeful that Red Bull can use this time to improve the car both in terms of reliability and pace.
"It's very difficult, but I'm not calling us favourites for that," he said of Red Bull's chances in the Australian Grand Prix.
"We haven't done enough laps, the speed is not there compared to some other teams so we have to wait and see when we get there.
"But surely things will calm down. We have to use the two weeks that we have until then to fit new parts to the car and build it to the best knowledge that we currently have."
Red Bull has completed just 1711km during pre-season testing, ahead only of Marussia and Lotus. By contrast, Mercedes has logged almost 5000km.
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