Tubbs is Crawley's leading goalscorer this season
Matt Tubbs scored the only goal of the game as Crawley made it four straight wins with victory at Northampton.
Michael Jacobs twice tested Crawley keeper Scott Shearer before Tubbs netted his eighth of the season with a deflected 10-yard shot.
Home keeper Sam Walker denied Tyrone Barnett a second, while John Akinde and Tubbs both fired over for the visitors.
Jacobs curled a shot against the bar for the hosts, who almost levelled late on when Kelvin Langmead headed wide.
VIEWS FROM THE DRESSING ROOM
Northampton Town boss Gary Johnson told BBC Radio Northampton:
"We didn't play well today. Our flair players didn't turn up so that's disappointing and we didn't create enough chances.
"If you had a crystal ball as a manager then you wouldn't play them in the first place but they're good players and they can show things but on the day it wasn't with them.
"If that doesn't happen for your flair players then your team is not going to do enough to win."
Crawley boss Steve Evans told BBC Sussex:
"It was a hard-working performance and we dominated possession for long spells. I think if our quality was a little bit better in the final third we would have killed the game off.
"We restricted Northampton to a shot from distance that hit the bar, but other than that they hardly made a chance.
"Arguably we've been very, very solid. When we've got our big players back and available for selection, we're capable of winning football matches."
Northampton 01 Walker 03 Corker (Arthur - 46' Booked ) 05 Tozer 14 Johnson 25 Westwood 28 Langmead 04 Baldock (Savage - 79' ) 17 Jacobs 02 Young (Robinson - 67' ) 09 Jackson 10 Akinfenwa Substitutes 30 Snedker 15 Turnbull 29 Arthur 08 Robinson 27 Savage Crawley Town 25 Shearer 05 McFadzean Booked 19 Griffiths Booked 26 Eastman 28 Davis Booked 08 Torres 13 Hunt 15 Bulman 27 Drury (Wilson - 90' ) 09 Tubbs (Doughty - 89' ) 23 Barnett (Akinde - 65' ) Substitutes 01 Kuipers 16 Wilson 21 Doughty 22 Neilson 17 Akinde