Kyle Coetzer hit an unbeaten 150 to put Northamptonshire in a strong position at the end of the first day of their LV= County Championship Division Two game against Leicestershire at Grace Road.
It was a championship-best for the 29-year-old opening batsman, who had scored only 133 runs in his previous nine innings.
Andrew Hall also made an unbeaten half-century as the table-toppers reached the close on a healthy 320 for four after being put into bat.
The century was the seventh of Coetzer's career and second for Northants, who he joined two years ago. His previous one also came against Leicestershire last season.
But the bottom-of-the-table hosts had only themselves to blame for allowing Northants to take such an early grip on the game. The bowlers failed to make the most of a green-tinged pitch and were not helped by dropped catches.
A total of five went down in the day, the most costly proving to be Coetzer - who was grassed on 25 when Nathan Buck failed to hold on to a sharp return chance.
Another major problem for Leicestershire was the number of boundaries conceded.
Coetzer took 120 balls to reach 50 but hit 11 fours and, at the point of move to three figures, had struck 19 boundaries in a 191-delivery innings.
In all, Leicestershire conceded a total of 202 runs in boundaries, 49 fours and a six.
After the early departure of Matthew Spriegel, trapped lbw by Alex Wyatt for seven, Coetzer and David Sales shared a stand of 65 in 24 overs.
Sales was dropped on 21, but had his off stump knocked back with Wyatt's first ball after lunch to go for 32.
The impressive Coetzer then dominated a third-wicket partnership with Alex Wakely, who was shelled at slip off Ollie Freckingham early in his innings. But he hung around to share in a stand of 74 before edging to slip off Buck for 18.
Robert Keogh was caught at mid-on for the same score off Michael Thornely, but Hall then joined forces with Coetzer to punish the Leicestershire attack in the final session.
The fifth-wicket pair hammered 120 runs in 34 overs with Coetzer reaching his 150 off 277 balls, including a six and 26 fours, and Hall unbeaten on 65.