With the game tightly poised with 35 minutes to go, manager Darren Way introduced the pair, and Bird gave his side the lead just three minutes after coming on.
Tahvon Campbell made it 2-0 with a stunning strike from 25 yards to give him his first goal in Green and White, but Crawley’s own substitute Lee Barnard made a nervy last ten minutes as his header made it 2-1.
Yeovil started the game brightly, and were so close to going ahead twice in the first fifteen minutes. Both Nathan Smith and Shaun Jeffers were inches away from opening the scoring, but twice Crawley somehow kept the ball out of Callum Preston’s goal.
The Glovers were dominating the opening exchanges, but the visitors were aggrieved after a freekick into the area. Centre-back Josh Yorwerth appeared to be tripped inside the box by Jeffers, but Chris Kavanagh waved away their appeals.
Lone striker Harrold was inches away from breaking the deadlock as he met a cross as Crawley settled into the game, but it was Yeovil who should have gone in front with five minutes to go in the first half.
Walsh’s pass set Roberts flying down the right wing, and the young right back’s byline cross was flicked towards goal by the heel of Zoko, only for the Ivorian’s shot to deflect off a Crawley defender and behind for a corner.
Yeovil should have taken the lead in the first stages of the second half. Jeffers raced clear but Preston denied both him and Compton’s followup, but Crawley scrambled away.
With ten minutes gone after the interval, Artur Krysiak was suddenly called into action, and the Pole stopped Harrold’s goal-bound header from Walton’s whipped cross.
But Yeovil did take the lead just after the hour mark. Zoko flicked a cross into the path of substitute Bird, and the striker showed exactly why Way brought him on just three minutes earlier as he toepoked the ball past Preston to put the Glovers in front.
The Glovers were desperately unlucky to not have doubled their lead with twenty minutes left. Bird’s cross-found fellow sub Tahvon Campbell and the on-loan striker headed against the bar, but the ball didn’t bounce over the line.
As the rain started to blow across Huish Park, former Glover Lewis Young raced clear on the counter. His run into the box looked threatening, but at the vital moment slipped and his shot blazed over into the terrace.
But Yeovil did make it 2-0, and what a way to do it! Tahvon Campbell made up for his missed header, as the West Brom loanee cut in off the left flank and rifled past Preston from 25 yards to score his first ever goal as a professional in some style.
Not even the drizzle could dampen the Yeovil fans spirits, but Crawley’s own substitute Lee Barnard halved the lead with eight minutes to go, as his flicked header went over Krysiak and into the net.
Man of the Match Liam Walsh was given a standing ovation as he left the pitch, and Yeovil held their nerve for a crucial win in the race to stay in League Two.
Yeovil: Krysiak- Roberts, Sokolik, Smith, Dickson- Dolan, Tozer, Walsh (Dawson 85’)- Zoko, Jeffers (Campbell 56’), Compton (Bird 56’).
Subs not used: Weale, Laird, Gillett, Allen.
Crawley: Preston- Walton, Bradley, Edwards, Young (Jenkins 78’), Ashton, Harold (Barnard 78’), Deacon (Tomlin 67’), Yorwerth, Smith, Atkinson.
Subs not used: Fenelon, Bawling.
Attendance: 3424 (139 away)