Michael Symes and Adam McGurk scored in the last seven minutes after the hosts had fallen behind to goals from Anton Forrester and William Edjenguele.
Blackwell was disappointed not to see his team win but insists there are plenty of positives to take home from the Pirelli Stadium.
He said: "I thought our first-half performance was as good as any I've seen from a team at this level for a long time.I thought we looked a real class outfit and created some good chances.
"We knew they'd throw the kitchen sink at us in the second half and I think that maybe we should have dealt with the balls into our box a little bit better. Other than that, I'm pleased with the boys.
"We were 2-0 up and thoroughly deserved it and maybe should have gone on and killed the game, but we're an effective outfit, a strong unit, and I'm more than happy with what I've seen.
"We've got lads who are 19 years of age and they'll develop as the season goes on."