Northampton comfortably moved into the Carling Cup second round after seeing off League One Brighton 2-0 with first-half goals from Michael Jacobs and Billy McKay.
The League Two outfit were never seriously troubled by a Brighton side who were reduced to 10 men late in the first half by the dismissal of Matt Sparrow. And although they showed more intent in the second half, the visitors were never able to claw back the two-goal deficit.
Jacobs, 18, grabbed the opening goal on his full debut as early as the 12th minute when he cut inside before beating Michael Poke from 15 yards.
Six minutes later McKay doubled Northampton's advantage with a diving header at the far post from a pin-point cross from the impressive Ryan Gilligan.
Sparrow was shown a straight red in the 35th minute for hitting out at Abdul Osman and Brighton never really recovered.
The Cobblers should have increased their advantage in the second half with skipper Andy Holt heading over from Nathanial Wedderburn's cross, while the latter went close himself with a diving header.