The County go into the final day at Wantage Road on 347 for seven in reply to the visitors' 519 for nine declared, still needing 22 runs to avoid the follow on.
Lewis McManus will start the day unbeaten on 29 while Tom Taylor is 20 not out, and Vasconcelos is backing the pair and those that follow to get the job done.
“It was a good day’s cricket really, I still think we're in a decent position going into the last day," said the Northants captain, who earlier in the day made 71.
"The longer we go, the more, only one result comes into it.
"So, that's the challenge in the morning is how long we can keep going.
"The first target is get past that follow on and then get as close as we can to them, if not past them."
The only down side to a good day for Northants was that no batter went on to make a century, despite them all making good starts.
Nightwatchman Matt Kelly hit 25, Luke Procter 76, Rob Keogh 45 and Josh Cobb 41, but as a unit, the County did what was required.
“Most of us went past 50 partnerships," said Vasconcelos. "That's one good thing, is we never we never had one of those bang-bangs that we could have done very easily.
"But we're a bit disappointed in firstly, the batters not going on to get that big score and then secondly, not that big partnership."
The captain also had words of praise for the in-form Procter, who has now scored two centuries and two fifties this summer.
“Luke Procter is playing the best I've ever seen him play," admitted Vasconcelos.
"If he can keep going like this, it's going to be great for us as a team.
"Not only is he scoring a lot of runs but very important runs and he’s bowling very well as well, so he’s been great for us this year and long may it continue.”
Kent bowling coach Simon Cook said his side were intent on taking early wickets on Sunday, in the hope they can still force their first win of the season.
“The discipline throughout the whole of Saturday was brilliant with all of the bowlers and we got the rewards at the end of the day," he said.
"You’ve just got to hope we can get a couple of quick ones on Sunday and we can enforce the follow-on if that's possible.
“It will come down to the first half an hour. On these sorts of pitches, it's tough.
"And hopefully that kind of nervousness around getting close to that total will mean that we can capitalise on that. It’s realistically, the only way we'll probably be able to force a result."
Play starts at 11am on Sunday morning.