The visitors were 2-0 up heading into stoppage time thanks to goals from David Wheeler and Ryan Harley but Richard Duffy pulled one back - his second in as many games - before Grant saw his low shot take a couple of deflections before deceiving visiting goalkeeper Christy Pym to rescue a point for the Magpies.
The Nottingham Forest loanee said: "I loved every minute of it. When you come off the bench you have to make an impact and thankfully I did.
"The manager told me to go on, work hard and give us a little bit of magic whether it's by scoring a goal or setting one up and that's what I did so I'm buzzing."
Grant's goal was his first since he scored on his full Forest debut in an EFL Cup tie at Tottenham in 2014 and he was delighted to be back on the scoresheet.
"I'll definitely claim it!" he laughed. "I went to put it in the bottom corner but it has taken a little nick and gone underneath the goalkeeper.
"It's good we managed to get a draw because it's a massive result and we have to take this into Saturday against Leyton Orient now.
"I thought we battled hard but gave some sloppy goals away. We've fought and got ourselves back into it."