The winger saw 15 minutes of action in what ended in a 1-1 deadlock at St. James' Park.
With the draw, the two teams are set for a replay to decide who goes through to the fourth round.
After a barren first half, Bradley Dack put Championship side Blackburn ahead with a cool finish in the 56th minute, having been set up by Elliott Bennett.
The hosts, however, restored parity in the 84th minute through Matt Ritchie, who converted a spot-kick after Ayoze Perez was fouled in the box.
Atsu joined the action in the 75th minute, taking the place of Jacob Murphy.
The match was his 16th appearance involving eight substitute outings for The Magpies in all competitions this season.
Handed two successive starts before Saturday's fixture, Atsu will hope to return to Rafael Benitez's XI when they play away to Chelsea in the Premier League in their next game.
The winger joined Newcastle on a permanent contract from Chelsea in 2017 following an initial loan deal.