A goal from Alex Kempster deep into stoppage time took Whitley Bay through to the next round of the Northumberland Senior Cup on a foggy night at Hillheads.
Visibility steadily deteriorated through the second half amid fears that the game would have to be abandoned if extra-time was required.
Team Northumbria, third top of the Northern League second division after an excellent start to the season, enjoyed the greater share of possession but failed to capitalise.
Louis Storey wasted a glorious chance after 14 minutes when he side-footed wide when clean through on goal.
Having spurned that chance, when they did threaten the Bay goal the visitors found their former keeper Andy Jennison in excellent form.
Ben Dibb-Fuller failed to find the target after 20 minutes while Joshua Draycott drove a free kick straight at the keeper 13 minutes later.
Whitley’s best two chances of the half fell to Jake Richardson, whose perfectly struck 20-yard volley crashed off the bar with Mundy well beaten.
Five minutes later the Students keeper did superbly well to push away the midfielder’s downward header that looked certain to put Whitley in front.
Kris Hughes was a matter of inches wide with a first time effort after good work from Kempster and Adam Shanks.
Just past the hour Mundy was cautioned after racing out of his area and bringing Kempster down as he closed in on goal, but then at the other end Dibb-Fuller was denied by an excellent save from Jennison.
With the fog closing in, Spence headed high over the Whitley bar following a free kick 20 yards from goal.
With nine minutes remaining, Callum Anderson was dismissed by referee Dean Hulme for what was deemed to be a dangerous tackle, although many close enough to see the incident felt it was a harsh decision.
Team North failed to make the most of their advantage and it was Whitley who finished the stronger.
Chris Reid’s close range header from a Mark Bertram corner hit the outside of the post before a long mazy run out of defence by Hughes set up Shanks whose shot failed to trouble Mundy.
At this stage it was difficult to see from one end of the pitch to the other, but two minutes into added time, Kempster seized on a weak back pass by defender Jake Armitage and took the ball round the keeper and slotted it into the net from eight yards to the delight and relief of his team-mates, who were not relishing the prospect of extra-time with the FA Cup tie against Chorley coming up on Saturday.
Two additional minutes were played before Whitley could celebrate a hard fought victory which extended their unbeaten run to nine games.
It was certainly not a classic display, and assistant manager Paul Johnson described it as a poor Bay performance but gave credit to his team for grinding out a result against difficult opponents and keeping their successful run going.
Whitley Bay: Jennison, Day, McDonald, Anderson, Flynn, Reid, Hughes, Bertram, Shanks, Richardson (Bell 66), Kempster. Subs not used: Young, Gladstone, Laws, Lumsden.