Matty Fryatt, the teenage striker linked with several Premiership clubs, was denied a fourth-minute goal by a superb save from Yeovil's Chris Weale, and the keeper repeated it two minutes later when a goal seemed inevitable.
The Saddlers continued to pen Yeovil back and took the lead when they were awarded a penalty in the 27th minute.
Darren Wrack was brought down by a rash challenge from Colin Miles near the byline. He lay motionless for a long time and it was seven minutes before the kick could be taken - Fryatt sending Weale the wrong way from the spot.
By then Wrack was on his way to hospital with a broken left leg.
If there was a silver lining to this unfortunate incident it was that it meant the introduction of Michael Husbands. The midfielder, making his debut, caused the Glovers plenty of problems with his pace.
Just before the interval Yeovil boss Gary Johnson sent on last season's top scorer Phil Jevons, together with Arron Davies, who missed the last match on Wales Under-21 duty
Jevons, League Two's top scorer last term with 29, has been out with a groin injury. He made an immediate impact and in a much better second-half Yeovil performance got the equalising goal - his first of the season.
Pablo Bastianini rounded the goalkeeper and slipped the ball to Jevons who netted from close range.
That was in the 65th minute, and five minutes later, speedy winger Kevin Gall back-headed the winner. He had previously missed a much easier chance.