Boro replaced County in second place in League One after they came from behind to beat their hosts in a topsy-turvy game at Meadow Lane.
Jamal Campbell-Ryce put the home side ahead from the spot after his team-mate and regular penalty taker Jeff Hughes had earlier fluffed his lines from 12 yards. However, Stevenage deservedly scored a penalty themselves when Lucas Akins finished after Alan Sheehan had handled and received his marching orders to leave County with 10 men for the remaining seven minutes.
It was down to substitute Shroot to make sure the visitors took away all three points with a dramatic injury-time winner. Curle felt the away side had come to Meadow Lane with a gameplan to get a point and said to be beaten in that manner must be used as a learning curve.
"Stevenage came with a gameplan to come here and frustrate from minute one," said Curle. "I think, in their own minds, if they were to get a point they would've been more than happy, but they have nicked all three. Of course it's disappointing. I think overall we have played well and if we score both the penalties I think we would have gone on to win.
"It's a learning curve for the players. You've got to know where you are in the game and where you are on the pitch. Stevenage are a decent team though, so there is no shame in losing to them, but obviously at the minute it's a bit hard to take after losing like that."