Whoever prevails from the contest at Sixfields on Wednesday evening will set up a Wembley showdown with either Port Vale or Swindon Town.
Despite having ended the regular campaign with a six-game unbeaten streak, Northampton went into the opening fixture of this semi-final full of disappointment after narrowly missing out on automatic promotion.
Jon Brady had a big job on his hands to keep his squad's spirits up, and it appeared that he had failed with that task when Northampton went 2-0 down at Field Mill within 32 minutes.
However, Ali Koiki's effort after the break has left this tie delicately poised with both managers having reasons to believe that their team are favourites to reach the final.
If anything, Northampton were unfortunate not to get back on level terms before the end of the contest on Saturday, the Cobblers having built a certain level of momentum ahead of the second instalment.
Although they only put together the seventh-best home return during the regular campaign, Northampton still collected 44 points from 23 fixtures, losing just five times.
Mansfield's efforts on the road were far inferior, Nigel Clough's men winning just seven of their games and ending the campaign on a run of just five points from as many outings.
On a positive note, the Stags are on a five-match unbeaten streak, while they have scored twice in each of those contests with the goals being shared around the squad.
Leading marksman Rhys Oates ended a six-game wait for another strike on Saturday, the 27-year-old getting on the scoresheet for the first time since the end of March.
The corresponding fixture during the regular campaign took place all the way back in October, Northampton prevailing by a 2-0 scoreline on that occasion.
Northampton will be able to call upon first-choice goalkeeper Liam Roberts, who served a one-match suspension for the first leg.
Aaron McGowan may come back into contention at right-back after not featuring since April 30.
While Clough could be prepared to stick with the same Mansfield XI from the first leg, he has revealed that a number of players are fitness doubts.
Newcastle United loanee Matty Longstaff felt "under par" during his hour-long appearance at the weekend, Stephen Quinn is carrying a hip issue, with George Maris and Stephen McLaughlin carrying knocks.
Northampton Town possible starting lineup:
Roberts; Mills, Horsfall, Guthrie, Koiki; Sowerby, McWilliams; Felix-Eppiah, Pinnock, Hoskins; Appere
Mansfield Town possible starting lineup:
Bishop; Perch, O'Toole, Hawkins, McLaughlin; Longstaff, Maris, Quinn; Murphy; Bowery, Oates
We say: Northampton Town 1-1 Mansfield Town (Mansfield to win 3-2 on aggregate)
Having kept themselves in the tie, Northampton will fancy their chances when it comes to using home territory to their advantage. However, we feel that Mansfield will do just enough on Wednesday evening to come through this tie, potentially benefitting from a goal in the first half on the break.
For additional data used by our team to analyse our suggested result please click here.