Craig was not shy in saying the Reserves weren't good value for their two-goal cushion and could easily have been three down before the break at Kingston Park.
A penalty from Michael Chopra - his fourth goal in three games - and a bizarre goal from Martin Brittain put United in a strong position with 13 minutes left, before late strikes from Gary Harkins and Keith Barker tied things up for Rovers.
Tommy Craig: "It was a game we never controlled, it was scrappy and untidy. We were fortunate not to be losing at half-time, Blackburn created more chances than we did. We were better in the second half, but I looked at the clock when we were 2-0 up with 15 minutes left and thought this isn't finished."
United's debutant Dutch goalkeeper Tim Krul had a nervous start but survived an early onslaught by Blackburn, who hit the woodwork twice through Keith Treacey and Sergio Peter inside the opening quarter.
Ex-Liverpool man David Thompson was adjudged to have handled Chopra's shot on the line, but after a long chat with his linesman referee Peter Varley showed the Rovers midfielder only a yellow card before pointing to the spot.
Brittain's cross-cum-shot found the back of Richard Lee's net, but Rovers clawed one back 10 minutes later when Harkins' low drive left Krul with no chance, and then with eight minutes left United were suddenly back to square one when Andy Taylor crossed from the left wing, Craig Ramage didn't deal with it properly, and Barker's shot squirmed past Krul.
NEWCASTLE UNITED RESERVES: Krul, Baxter, Cave, Elliott, Ramage, Gate, Brittain, Smylie (Farman 58), Walton (Shanks 87), Chopra, Ameobi. Not used: Forster, Huntington, Finnigan.
BLACKBURN ROVERS RESERVES: Lee, Kane, Taylor, Harkins, Barr, Nolan, Treacy, Thompson, Johnson, Barker, Peter. Not used: Byrom, Fielding, Stopforth, Welch, Thomson.