Northants are on course to claim a win that will just about keep their Specsavers County Championship Division Two promotion hopes alive.
The County need to reach 218 to beat Glamorgan on the final day of the clash at Cardiff.
Northants finished on 42 for one at the close of the third day, with Ben Duckett the man out for 23.
Rob Newton (15no) and nightwatchman Simon Kerrigan (0no) will start the final day's action in the middle.
Glamorgan were eventually bowled out for 320 in their second innings, with Rory Kleinveldt and Richard Gleeson both taking three wickets.
That left third-placed Northants with a victory target that they are confident of reaching.
And if they can do so, they will still have a slim chance of finishing in the top two with two matches to go.
"Another day of hard graft from our bowlers," tweeted Northants skipper Alex Wakely. "They have set this game up nicely.
"Tomorrow is a day we simply have to win to stay in the hunt."