Lewis Hamilton laid down the marker by posting the fastest times in the opening two free practice sessions of the Japanese Grand Prix on Friday making him the overwhelming favorite to win the race Sunday.
Vettel's afternoon effort, while quicker than his best attempt in the first 90 minutes, was still slower than Hamilton's morning benchmark, which the Briton had set on the less grippy soft tyres.
That was 0.833 seconds quicker than Vettel, who improved from fifth in the morning to third quickest in the second session but had no answer to Hamilton's pace.
He and team-mate Kimi Raikkonen struggled with their tyre life as the Mercedes pair of Hamilton and Valtteri Bottas struck a psychological blow by topping both sessions ahead of this weekend's qualifying and race. I was much better than I had ever been through those particular corners.
"So now I've just got to stay on it, keep going, keep working".
But even after a dominant showing from Hamilton in practice at the Japanese Grand Prix, team boss Wolff claimed there is still much more to come from the Silver Arrows.
It was a supreme day in the vehicle for Hamilton, who led team-mate Valtteri Bottas by four tenths in both sessions.
"I think I've said many times that we have a strong auto, but I don't think, against the people's opinions, that we had a dominant vehicle at any point this year", the German said.
Asked if they can bridge the large Friday gap to Mercedes, Vettel replied: "Time will tell, I don't know".
"The first section is the best rollercoaster ride that I've felt in a Formula One vehicle. If we can grasp pole tomorrow, that is great, but if not we need to be there just right behind".
"Also, in Russian Federation, it seemed that we were a lot ahead of everyone else on Friday, but in qualifying it gets more intense".
"Now, you never know where you are in comparison to others, maybe they have done smaller steps or bigger steps, I don't know, but I'm pretty sure speaking to all our engineers that we are where we would like to be or where we wanted to be".
"I've just been giving thanks all day today because this is what I've always wanted to do".
"We know what the auto can do and we need to focus on that and try to get everything out to put us in the best possible position".