With Michael Dobson pulling the strings in midfield and Butler a constant threat, Walsall were never second best to their hosts and only some last-ditch defending and excellent goal-keeping by Matthew Gilks sent the teams in level at the break.
Gilks made one fine save after a long throw from the left had been flicked into the path of Mark Wright, and in the dying seconds of the half he kept out Butler who burst into the penalty area and fired his shot from a tight angle.
The young keeper saved his best until last as from the subsequent corner defender Anthony Gerrard must have thought that his powerful header was heading fro the net before Gilks produced an instinctive save to claw it away.
With the first action of the second half, Rochdale's leading scorer from last season, Rickie Lambert, came within inches of breaking the deadlock with a 30- yard free-kick, but with their next attack Walsall took the lead.
A neat interchange of passing between Mark Wright and Hector Sam completely opened up the home defence and allowed Butler to slot the ball past the unprotected Gilks.
In Rochdale's best period Lambert saw another free-kick brilliantly saved by Clayton Ince and shaved the far post after good work by co-striker Iyseden Christie, but that was the nearest that Rochdale came to breaking down a very solid Sadlers rearguard.
Referee Mr Foster confused the home crowd when he denied Rochdale what should have been a clear-cut penalty when defender Allan Picken clearly fouled defender Simon Ramsden, his raised foot so high that it parted Ramsden's hair, but the referee decided instead of pointing to the spot to give an indirect free-kick inside the penalty area which saw Lambert's shot deflected away to safety.
Although Rochdale manager Steve Parkin threw on all three substitutes, they never again saw the whites of keeper Ince's eyes.