After losing to Chesterfield on Saturday - their first defeat in 12 League games - Notts can have no complaints about this second successive setback to a vastly superior Rochdale side.
The visitors dominated the first 45 minutes, but were unable to match their inventive approach play with accurate finishing and Notts were fortunate to be level at the break.
Only two minutes into the second half Notts were thrown a lifeline when Rochdale central defender Nathan Stanton floored Myles Weston in the box.
It was County's third penalty award of the season and, as with the other two, Jamie Forrester took it brilliantly to convert with a piledriver low into the corner.
Not for the first time this season Notts were unable to hold on to the lead for long and Rochdale, who came back strongly, deservedly equalised on 63 minutes.
The final ball from Gary Jones picked out Lee Thorpe, who drilled it passed Russell Hoult from the edge of the area.
Rochdale kept up the offensive and looked even sharper and more dangerous when they replaced midfielder John Thompson with the sensational teenager Will Buckley on 51 minutes.
When a Notts attack broke down Buckley picked up the ball in his own half of the field before sprinting into the Notts penalty area and feeding Thorpe with a slide-rule pass.
The big striker drew out Hoult before sliding the ball over the line for his second and for what, ultimately, turned out to be the winner.
Rochdale continued to pile on the pressure, creating far more chances than County, with the home side simply being unable to get back into the game.
It's Notts' first home defeat of the season and after the earlier run they now have some big problems to sort out.