The Cobblers made the early running and should have gone ahead, as Marc Richards got goalside of Cian Bolger, lofting a neat ball to Michael Smith who rattled the woodwork from barely five yards out.
Justin Edinburgh's side seemed determined to stamp their mark on the game, Michael Smith firing wide from close range as the high-flying hosts looked to be limping to the break.
But the game turned in a second when Adam Smith hesitated under pressure from Ball.
The Fleetwood striker's chip was gathered by Devante Cole, who was denied at the first attempt but pounced on the rebound to find the net from the tightest of angles.
Ball might easily have doubled Town's tally within minutes of the restart, another moment of uncertainty going unpunished as his shot slipped just wide of the back post.
Fleetwood did soon find their second, Bobby Grant skipping around two men and firing past Smith from the right of the six-yard box.
A second goal in the space of four minutes ended any hopes of a Cobblers comeback, Ball this time the architect and scorer.
He made the most of David Buchanan's slip, racing in from the left and picking the moment to lift the ball over the advancing Adam Smith to bag his 13th goal of the campaign.
Match report supplied by the Press Association.
Match ends, Fleetwood Town 3, Northampton Town 0.
Second Half ends, Fleetwood Town 3, Northampton Town 0.
Conor McLaughlin (Fleetwood Town) wins a free kick in the attacking half.
Foul by John-Joe O'Toole (Northampton Town).
Foul by Victor Nirennold (Fleetwood Town).
John-Joe O'Toole (Northampton Town) wins a free kick on the right wing.
Jak McCourt (Northampton Town) is shown the yellow card.
Conor McLaughlin (Fleetwood Town) wins a free kick in the attacking half.
Foul by Paul Anderson (Northampton Town).
Substitution, Northampton Town. Jak McCourt replaces Matthew Taylor.
Attempt missed. Hiram Boateng (Northampton Town) left footed shot from the right side of the box is close, but misses the top left corner.
Attempt saved. Matthew Taylor (Northampton Town) left footed shot from outside the box is saved in the bottom left corner.
Substitution, Fleetwood Town. Cameron Brannagan replaces Kyle Dempsey.
Attempt saved. Ashley Hunter (Fleetwood Town) left footed shot from outside the box is saved in the centre of the goal.
Ashley Hunter (Fleetwood Town) is shown the yellow card for a bad foul.
Foul by Ashley Hunter (Fleetwood Town).
Matthew Taylor (Northampton Town) wins a free kick on the right wing.
Zander Diamond (Northampton Town) is shown the yellow card for a bad foul.
David Ball (Fleetwood Town) wins a free kick in the defensive half.
Foul by Zander Diamond (Northampton Town).
Substitution, Fleetwood Town. Ashley Hunter replaces Devante Cole.
Corner,  Fleetwood Town. Conceded by John-Joe O'Toole.
Corner,  Fleetwood Town. Conceded by Zander Diamond.
Bobby Grant (Fleetwood Town) wins a free kick on the left wing.
Foul by Neal Eardley (Northampton Town).
Substitution, Fleetwood Town. Victor Nirennold replaces George Glendon.
Substitution, Northampton Town. Paul Anderson replaces Marc Richards.
Attempt missed. David Ball (Fleetwood Town) right footed shot from outside the box misses to the left.
Amari'i Bell (Fleetwood Town) wins a free kick in the defensive half.
Foul by John-Joe O'Toole (Northampton Town).
Substitution, Northampton Town. Hiram Boateng replaces Gregg Wylde.
Goal!  Fleetwood Town 3, Northampton Town 0. David Ball (Fleetwood Town) right footed shot from the left side of the box to the centre of the goal. Assisted by Ben Davies.
Goal!  Fleetwood Town 2, Northampton Town 0. Bobby Grant (Fleetwood Town) right footed shot from the right side of the box to the top left corner.
Conor McLaughlin (Fleetwood Town) wins a free kick in the defensive half.
Foul by Gregg Wylde (Northampton Town).
Foul by George Glendon (Fleetwood Town).
David Buchanan (Northampton Town) wins a free kick in the defensive half.
Attempt missed. Cian Bolger (Fleetwood Town) header from the centre of the box is close, but misses the top left corner.
Corner,  Fleetwood Town. Conceded by Adam Smith.
Attempt missed. David Ball (Fleetwood Town) right footed shot from the right side of the box is close, but misses to the left.
David Ball proved Northampton's undoing, creating one and scoring another as high-flying Fleetwood earned victory, their 17th successive game without defeat.