Northamptonshire 142 for 4 (Newton 69*, Keogh 50) trail Leicestershire 519 (Pettini 117, Eckersley 107, Raine 64, Sanderson 6-58) by 377 runs
Ned Eckersley's third consecutive first-class century saw Leicestershire take control at Wantage Road with a first-innings total of 519 before reducing Northamptonshire to 142 for 4 at the close on day two, trailing by 377.
Eckersley became just the third man to make three centuries in successive matches for Leicestershire, following Ben Smith in 2001 and Charles Dempster before the war.
He helped Leicestershire into a commanding position. They found two early wickets in the Northants reply before the home side recovered from 33 for 2 with pleasant fifties for Rob Keogh and Rob Newton. But when Keogh dragged a cut into his off stump to end a third-wicket stand of 91, and nightwatchman Azharullah was caught at short leg in the final over of the day, the visitors were firmly on top.
Their position on the second day was set up by Eckersley's determined century. He steered his side through the second new ball on the first evening - surviving a tough dropped chance on 4 when pulling towards midwicket - and then cajoled the lower order to help his side post their highest total of the season.
When the eighth wicket went down, Eckersley had 71 but he found a game partner in Ben Raine, who, after a skittish start, settled to make a season's best 64. The pair added a record ninth-wicket stand for Leicestershire against Northants of 123 and Eckersley went through a hundred in 156 balls with 11 fours and a six.
Raine eventually fell to Keogh's offspin and Eckersley was last man out trying to lift the same bowler over long-on, Leicestershire eventually bowled out after 144.2 overs.
The visitors then struck in the fifth over of the Northants reply with David Murphy tamely chipping a back-foot drive to extra-cover and Alex Wakely edging Rob Sayer's offspin to Niall O'Brien. At that stage, it was a very poor day for the home side who again allowed Leicestershire to recover from morning pressure.
Ben Sanderson took 3 for 19 in an opening eight-over burst to bring up a third five-for of the season and leave the visitors 356 for 8. First to go was Mark Pettini, adding just eight to his overnight 109, getting lifter that came off the shoulder of the bat to point. Clint McKay edged a back-foot drive behind the wicket and Sayer got a bottom edge into his stumps trying to leave three balls later.
But Eckersley remained calm, Raine settled and Leicestershire went on to take control of the game.