Grimsby Town ended their 20-game winless run as they picked up a precious three points against relegation rivals Chesterfield at Blundell Park.
In a tense game between two of the sides battling to escape the drop from League Two, it was Mitch Rose's late penalty which proved to be the difference.
The result moved the Mariners seven points clear of their visitors and gave the home fans in a bumper 6,780 crowd renewed hope ahead of the remaining four games of the season.
Two changes were made to the Town side that lost at Wycombe on Easter Monday, wih Siriki Dembele and JJ Hooper coming in for Zak Mills and James Berrett.
James McKeown started in goal, with Reece Hall-Johnson, Nathan Clarke, Danny Collins and Andrew Fox forming the defence.
Dembele, Luke Summerfield, Rose and Martyn Woolford were the midfielders, wih Scott Vernon partnering Hooper in attack.
Mills was named among the substitutes, along with Ben Killip, Harry Cardwell, Jamille Matt, Diallang Jaiyesimi, Gary McSheffrey and Sean McAllister.
Chesterfield were looking for a victory which would close the gap between themselves and the Mariners to just a point and give them real hope of avoiding the drop to the National League.
They would rely on the likes of Kristian Dennis, Zavon Hines and Andy Kellett to cause problems fo the Grimsby defence.
An early free kick from Louis Reed was headed clear by Hooper, before a foul by Alex Whitmore on Vernon gave the Mariners a free kick in a similar position near the halfway line. Summerfield's ball was cleared after Vernon had headed it on.
A low ball into the Town box from winger Jacob Brown was dealt with by Clarke, then another foul by Whitmore gave Grimsby another chance to put pressure on the Chesterfield goal, this time from 30 yards and in a central position. Fox sent his shot high over the bar.
The game's first corner came on seven minutes and went to the visitors after a cross from Drew Talbot was put behind. Hines' low delivery was deflected away for another one after it had reached Dennis at the near post and this time, the ball from the flag was cleared.
The away pressure continued with another corner, which was cleared by Summerfield, before visiting keeper Aaron Ramsdale's first involvement saw him get to a low cross from Hooper ahead of Vernon.
A low cross from Hall-Johnson on the Town right was deflected over the bar for a corner on 13 minutes but Summerfield's delivery was headed clear.
An opening for the visitors came on 19 minutes when a counter-attack saw Brown make progress through the middle before passing to Kellett, whose curling shot went over the bar.
A Fox free kick from near the halfway line was caught by Ramsdale, who quickly launched a counter-attack that ended with a good challenge by Hall-Johnson on Hines.
Another free kick, this time on the right, saw Clarke meet Fox's delivery but the ball was gathered by Ramsdale.
Hines dragged a low shot wide of McKeown's target, before a good run by Fox down the left resulted in a throw-in which was hammered clear by Talbot after Rose's throw was headed on.
A Grimsby corner on 26 minutes was dealt with by Ramsdale, then another long throw from Rose had the same result, with Talbot clearing.
A Kellett free kick was headed clear by Clarke as both sides continued to struggle to test the opposing goalkeeper, with Dembele failing to pick out a team-mate with a low cross and Hooper sending a long-range shot well over the bar.
McKeown had to make a save when Kellett shot from 18 yards after linking up well with Dennis, before Kellett had another chance when he picked the ball up inside his own half and made progress to the edge of the penalty area. His shot was weak though and McKeown got down to make a comfortable stop.
The visitors were starting to step things up now and McKeown was called into action again on 39 minutes, diving to push a volley from Dennis away for a corner, which was cleared.
Brown had a chance to create some danger after Fox slipped in his own penalty area but the winger's cross-shot was pushed out by McKeown for a corner. That turned into another flag-kick, which was cleared.
A chance then came at the other end when Hooper found space to shoot from inside the box but keeper Ramsdale was equal to it, coming off his line to block the striker's effort.
Kellett won another Chesterfield corner as the away side appeared to be finishing the half the stronger of the two teams but when the ball fom the flag was headed over the bar by Whitmore, it proved to be the last action before the interval.
The game had been played at a fast pace by two committed teams and both would be confident of building on their efforts further after the break.
No changes were made before the restart and Town had a chance within seconds when a long throw was met by Clarke but his header was kept out by Ramsdale at the expense of a corner.
A cross from Woolford was pushed away by Ramsdale, before a low cross at the other end was flicked clear by Clarke.
Fox was shown the first yellow card of the afternoon for bringing Kellett down on the halfway line and after the resulting free kick was lofted into the box, Whitmore's overhead kick was blocked before Town managed to get the ball clear.
Another foul on dangerman Kellett brought a booking for Woolford and gave Chesterfield a free kick in a central position. Reed's delivery was met by Dennis but he could not get any power on his header and the ball went through to McKeown.
Town's reponse saw a powerful effort by Dembele blocked, before the hosts again went close to opening the scoring when a header was blocked but after a scramble, the ball was eventually cleared off the line.
Jak McCourt replaced Hines for Chesterfield on the hour, before a chance for the Mariners saw Dembele fire high and wide from the edge of the box.
Dembele was booked for a foul on Talbot, then Town's first substitution saw Jaiyesimi replace Hooper.
Cardwell came on for Vernon on 71 minutes and the third and final home change saw McSheffrey come on for Dembele, who had landed awkwardly after jumping for a header.
Reed was booked for a foul on McSheffrey near the halfway line but the Mariners were unable to create any danger from the resulting free kick as the referee spotted a push by Jaiyesimi.
Chris O'Grady replaced midfielder Robbie Weir for the last nine minutes as Chesterfield boss Jack Lester added to his attack in a bid to force a breakthrough goal.
A long throw from Rose on 84 minutes was heaaded out for a corner but the ball from the flag was cleared.
Soon afterwards came another long throw and this time, the Mariners were given their golden chance to make that vital breakthrough. As the ball came into the box, a handball by Sid Nelson was spotted and the referee pointed to the penalty spot. ROSE stepped up and found the bottom corner of the net to spark wild celebrations around the ground.
A shot from Dennis was saved by McKeown as six minutes of added time was signalled and despite Chesterfield attacks, the Mariners saw out the remainder of the game to clinch their first win since December 9 and as the final whistle blew, more celebrations started.
Town are next in action on Saturday, when they face another massive game against fellow relegation rivals Barnet at Blundell Park.
1 James McKeown
31 Reece Hall-Johnson
23 Andrew Fox
5 Nathan Clarke (C)
6 Danny Collins
8 Mitch Rose
27 Siriki Dembele
19 Luke Summerfield
25 Martyn Woolford
9 JJ Hooper
21 Scott Vernon
30 Ben Killip
12 Zak Mills
20 Diallang Jaiyesimi
4 Sean McAllister
17 Harry Cardwell
29 Jamille Matt
10 Gary McSheffrey
1 Aaron Ramsdale
27 Bradley Barry
22 Drew Talbot
35 Sid Nelson
33 Alex Whitmore
28 Robbie Weir (C)
44 Jacob Brown
25 Louis Reed
24 Andy Kellett
41 Zavon Hines
9 Kristian Dennis
12 Joe Anyon
20 Laurence Maguire
17 George Smith
26 Jak McCourt
15 Joe Rowley
19 Louis Dodds
10 Chris O'Grady
Referee: Bobby Madley
Attendance: 6780 (1470)
Next Up: Barnet (H)