WREXHAM'S promotion challenge came to an end following a 5-4 defeat against Grimsby Town in the National League play-off semi-final at The Racecourse.
It was an epic contest that finished 4-4 after 90 minutes in front of the Red's owners, Ryan Reynolds and Rob McElhenney, who were again in attendance.
But Grimsby scored a 119th minute winner and they will face Solihull Moors or Chesterfield in the play-off final next Sunday.
The starting line-up showed two changes from the side that Parkinson selected for the FA Trophy final defeat the previous weekend.
Right wing-back Bryce Hosannah, available after recovering from a quad injury, took over from Liam McAlinden and centre-back Tyler French was recalled in place of Tom O'Connor.
Grimsby made a bright start and John McAtee fired into the roof of the net in the fourth minute but the goal was ruled out for offside.
The Mariners remained on top and Ryan Taylor only just cleared the bar with a header from a Danny Amos corner.
However, Wrexham broke the deadlock after 13 minutes.
Mullin was brought down in the area by ex-Reds' defender Luke Waterfall and the striker smashed home the resulting penalty off the underside of the crossbar.
But the lead was shortlived as Grimsby equalised just minutes later.
McAtee made room for a shot and he found the back of the net with a brilliant 25-yard strike.
Hosannah brought a superb save out of keeper Max Crocombe while Wrexham thought they had reclaimed the lead when Mullin converted Ben Tozer's long throw-in at the far post but the goal was disallowed for a foul.
It was Wrexham's turn to put the pressure on and Ollie Palmer's header deflected narrowly wide from a free-kick.
The Reds thought they should have been awarded another penalty when Hosannah knocked the ball past Crocombe in the area and was taken out by the Mariners goalkeeper but referee Adam Herczeg failed to award a spot-kick.
There was no let-up from Wrexham and Tozer's throw-in again caused problems in the Grimsby defence with Andy Smith almost putting through his own net but Crocombe pulled off a brilliant save.
Amos cleared the ball off the line when Jordan Davies headed the ball back across goal from the resulting corner
McAtee fired wide at the other end with the last chance of the first half, and Grimsby were quick out of the blocks following the interval.
Christian Dibble made a smart block to deny McAtee and then pulled off another save from Harry Clifton but the Mariners went 2-1 up on 47 minutes.
A cross came in from the right and Waterfall headed past Dibble.
Grimsby continued to press and Clifton's effort was parried by Dibble and the Reds' goalkeeper again thwarted the midfielder following a corner before Ben Fox was off target with his follow-up.
Amos went close for the Mariners but Wrexham equalised in the 63rd minute.
Luke Young sent in a corner and Tozer found the net with his header.
Just two minutes later and Wrexham went 3-2 ahead.
Tozer's throw in was flicked on by Palmer and Mullin converted.
Grimsby responded with Dibble keeping out Fox's drive but the Mariners levelled after 72 minutes.
It was another cross into the area that proved Wrexham's undoing with Taylor heading past Dibble.
There was a further blow for the Reds as Grimsby made it 4-3 on 78 minutes.
Wrexham switched off from a corner as unmarked substitue Emmanuel Dieseruvwe scored with a header at far post.
Mullin saw a shot brilliantly saved by Crocombe as Wrexham responded and the Reds were back on level terms in the 80th minute.
Davies rose highest to head home Young's corner to make it 4-4.
The midfielder wasn't far away with a spectacular volley which only just cleared the bar, Clifton shot inches wide for Grimsby with Dieseruvwe sliding in to convert while Callum McFadzean's effort was turned over the bar by Crocombe as the game swung from end to end.
Palmer headed over from Young's corner in added time but it remained all-square after 90 minutes.
Extra-time was needed to determine a winner and Davies had a penalty shout turned down when he went down in the area but there weren't any chances at either end before the turnaround.
The second half of extra-time saw Grimsby have an excellent chance to take the lead but substitute Tristan Abrahams fired into the side-netting with only Dibble to beat.
However, Grimsby scored in the 119th minute.
Jordan Cropper launched a throw-in and Waterfall found the net with a header to send the Mariners through to the final.
Wrexham (5-3-2): Dibble; Hosannah (McAlinden 72), French (Jarvis 120), Tozer, Cleworth (O'Connor 91), McFadzean; James Jones, Young, Davies; Mullin, Palmer (Hyde 106). Sub not used: Camp.
Grimsby Town (4-2-3-1): Crocombe; Cropper, Waterfall, Smith, Amos (Pearson 91); Holohan (Raikhy 102), Fox; Sousa, McAtee (Abrahams 87) Clifton; Taylor (Dieseruvwe 76). Sub not used: Maguire-Drew.
Attendance: 9,734 (1,214 from Grimsby).
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