This Tuesday, they have an opportunity to right their wrongs against 11th placed Oxford United.
Oxford come into the tie off the back of a disappointing 2-0 defeat against Blackpool on the weekend.
• Team news
Jon Brady's Northampton are likely to be without Jack Sowerby, who missed Saturday's tie after picking up a slight knock.
Aside from that, midfielder Scott Pollock is the only other absentee as he is recovering from a long term groin injury.
After another disappointing return in front of the goal, the forward positions are likely to see some rotation tomorrow night.
Karl Robinson has a fully fit Oxford squad to chose from and he could decide to make changes after a disappointing result last time out.
Olamide Shodipo could return to the starting XI after being benched on the weekend.
Anthony Forde may replace Alex Gorrin in midfield after the latter was hooked off at half-time against Blackpool.
• Predicted lineups
Northampton Town (4-3-3):
Mitchell; Kioso, Horsfall, Jones, Mills; Watson, McWilliams, Morris; Miller, Rose, Hoskins.
Oxford United (4-3-3):
Stevens; Hanson, Moore, Atkinson, Ruffels; Kelly, Forde, Brannagan; Taylor, Shodipo, Barker.
• Ones to watch
Ryan Watson - Northampton Town:
Ryan Watson has been one of Northampton's better performers this season having scored six goals from midfield.
The 27-year-old does an excellent job in both boxes for the Cobblers and has a hidden eye for goal.
If he is on his game tomorrow night, he could be the catalyst to Northampton's success.
Matt Taylor - Oxford United:
Matt Taylor has been Oxford's go-to man in the attacking department this season. He's scored 13 goals and notched two assists from 29 starts.
The 30-year-old has averaged a goal every 187 minutes this campaign. He has proved he can sniff out a chance in the 18-yard, with 12 of his 13 goals coming from inside the penalty box.
Taylor has created 33 chances for his team this season and has shown that he is a threat to opposing defenders because of his outstanding link-up play.
It is paramount that Northampton's defenders keep a close eye on Taylor because his ability in front of goal could be the difference on Tuesday night.
• Previous meetings
Out of the last 18 meetings between these two sides, Northampton have won nine, Oxford have won six, and there have been three draws.
When these two met earlier on in the season, Oxford thumped the Cobblers 4-0 when goals from Daniel Agyei, Shodipo and a Taylor brace sealed an emphatic victory for the Yellows.
The last time these two met at the PTS Academy Stadium, the game ended 0-0.
Last time out:
• Where to watch
This game kicks off at 19:00 GMT on Tuesday, 23 March 2021.
For Cobblers fans, the game can be watched by purchasing a live video match pass found in the iFollow section of Northampton's website.
The same process can be followed by Oxford fans, with their iFollow section being found here.
Both are for a cost of £10.