Steven Crook took four wickets as Northamptonshire controlled the first day of their LV= County Championship match against Glamorgan at Wantage Road.
After being put in on a grassy wicket, Glamorgan batted poorly despite a bright start as they were bowled out for 241, with all-rounder Crook picking up 4-66.
David Willey also kept up his rich run of form by claiming 3-54 before promotion-chasing Northants, seeking a first championship win in six, closed on 85 without loss.
Glamorgan's opening pair of Gareth Rees and Will Bragg initially frustrated Northants with a stand of 74.
Bragg was dropped on 28 by Alex Wakely at square-leg off Crook, but Rees fell for 39 when he edged Andrew Hall to David Sales at second slip.
Bragg followed three overs later when he nudged a super delivery from Crook to Northants wicketkeeper David Murphy.
Chris Cooke plundered 21 but gifted Crook a second wicket by clipping off stump with his bat to dislodge the bails.
Willey then picked up the prized wicket of Murray Goodwin, the former Zimbabwe international on 47 when he glanced a leg-side delivery to Murphy.
History repeated itself with the very next ball, although Murphy deserved credit for holding on when diving to his right to dismiss Glamorgan captain and wicketkeeper Mark Wallace.
Graham Wagg went cheaply when his loose drive off Willey was brilliantly taken at point by a plunging Wakely, who atoned for his earlier error.
Hall then caught John Glover at first slip off Crook following Murphy's fumble before Andrew Salter shanked the same bowler to Northants captain Stephen Peters at mid-off.
Trent Copeland got in on the act by having Jim Allenby, who hit 41, and Michael Reed caught behind to close the innings.
In reply, Northants openers Peters and James Middlebrook began just as confidently as their Glamorgan counterparts had done at the start of the day.
The duo saw off the 21 overs they faced without any alarm and had 39 and 38 to their respective names at stumps.