Alan Thompson (talking to the NUFC official website): "They can both be proud of themselves and they were a positive.
"Aaron is a young lad we signed from Plymouth; he's got good ability, can see a pass and has worked hard tonight and took his goal well.
"Patrick is another young player but we've seen tonight that he's a good defender.
"He's came in against experienced players and handled himself and can only learn from that."
Liam Henderson and Ryan McGorrigan also made their debuts as second-half substitutes.
Rotherham cancelled out Spear's opener before the break, then struck three times to take a 4-1 lead before Wesley Ngo Baheng netted a late consolation.