Brian Smikle's second-half goal gave Cheltenham a 1-0 win over 10-man Northampton.
A dull first half was only enlivened by the 22nd-minute sending-off of Northampton's Dean Beckwith.
The big defender received a red card when referee Dave Phillips adjudged him guilty of stamping on Shaun Jeffers after they tangled on the ground in an off-the-ball incident.
The Cobblers' best chance came when home keeper Scott Brown's athletic fingertip save denied Billy McKay.
Cheltenham dominated possession after the break and finally broke the deadlock on the hour mark.
Jeff Goulding's delicate flick put Smikle in on goal and the former West Brom forward made no mistake from close range.
Theo Lewis and Jeffers both missed chances to wrap up the game but the home side clung on nervously in the dying minutes as Andy Holt and Leon McKenzie squandered opportunities to level.
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