For much of this oh-so-vital match against East Fife it was Ally Love who looked the more potent threat for Danny Lennon's side.
But with just eight minutes left and Clyde in desperate need of a goal to keep them out of the relegation play-offs Goodwillie did what Goodwillie does.
East Fife keeper Jordan Hart did well to keep out substitute Josh Jack's strike from the edge of the box.
But when the ball found its way back into the danger area, inevitably it was Goodwillie on hand to head home and ultimately preserve his side's League 1 status.
Understandably, given there was more at stake for Clyde than for the visitors, the Bully Wee had started very much on the front foot and made almost all the early running.
In particular Ross Cunningham looked a threat and twice he was found unmarked inside the box. But on each occasion he failed to hit the target.
There was a warning for Clyde midway through the half when Spence flashed a header just wide from a Scott Agnew cross.
But in general most of the traffic was in the direction of the East Fife goal.
And the vital breakthrough finally came five minutes from the interval.
Cunningham's ball in from the left found Goodwillie and he turned the ball back across goal for Love to thump home from close range.
So Clyde went in at the break a goal up, but there was a nagging fear that those missed opportunities might come back to haunt them.
Whether it was manager Darren Young's words to his players at half-time, or the triple substitution he made, East Fife were a different team after the break.
Just four minutes after the restart Scott Rumsby clumsily grounded Ross Dunlop inside the box. Scott Agnew coolly send David Mitchell the wrong way from the spot and Clyde's advantage had gone.
East Fife had shown more in the opening few minutes of the second half than in the entire first period.
And things might have got even worse for the home side.
Former Cumbernauld Colts striker Sean Brown fired wide from a decent position and then beat Mitchell with a powerful header only to see it booted off the line by Mark Lamont.
It was now East Fife's turn to be in the ascendancy and Clyde - playing their 17th game in 48 days - had to dig deep.
But there was an edgy feel to their play, the fluency of much of their first half work negated by the knowledge that unless they could find another goal they were off to Stranraer on Saturday for a relegation play-off match,
Fresh legs helped as Danny Lennon firstly sent on Lewis Jamieson and Michael McGlinchey and then, as time threatened to run out, Jack for Barry Cuddihy.
And within two minutes of coming on Jack had played his part in the goal which finally brought a season unlike any other to an end.