"You're the toughest bloke I have ever hit in my life. Literally the toughest man in Australia."
The 40-year-old warhorse showed everything the great champions do — but it now seems impossible for his career to extend from here.
If it is his farewell, it is fitting of his stature as an icon of Australian sport.
The scorecard didn't tell the whole story.
Gallen was kept on the back foot for most of the fight, but showed some incredible heart to fight back in the final two rounds.
It wasn't enough.
Terzievski was awarded the victory via a unanimous decision (97-92 x3).
Earlier Olympic hero Harry Garside put on a clinic, while Nikita Tszyu — the brother of Aussie superstar Tim Tszyu and son of boxing legend Kostya Tszyu — became an instant star with a thunderous knockout win.
You can re-watch all the action on Main Event pay-per-view for $59.95, or live stream it for the same price on Kayo.
It was a fight that had everything.
Gallen simply didn't have any answers for his quicker opponent who was able to load up on shots from outside while stopping the former NSW State of Origin captain from getting up in his face and turning it into a slug fest.
The 40-year-old has won huge fights on pure grit alone in the past — but it wasn't enough on Wednesday.
Terziewski is the Australian heavyweight champion and there is potential for him to face off with previous champion Justis Huni in the future.
For Gallen, it may be the end of the road.
"I felt a little bit tired in the middle rounds... he won fair and square," Gallen said.
"I'm always humble in victory and humble in defeat.
"There's a saying, age is undefeated. It's caught up with me.
"You don't grow old between fights, you do between rounds.
"I'm not going to make any decisions now (about my future). I just felt in between those rounds I couldn't go like I normally go.
"I've had a great time involved in the sport ... we'll see what happens next."
Gallen loses nothing in falling short of becoming the first former footballer to win a national heavyweight title.
If anything his legend has grown.
Rugby league commentator Dan Ginnane wrote on Twitter: "Win lose or draw that should be it for Gal. Would go out with pride and on his feet. Forget dreams of SBW. Terrific 2nd career. Go and be a commentator for the next 20 years".
Code Sports boxing reporter Brendan Bradford wrote: "Say what you want about Gallen, but that guy is outrageously tough. It's insane".
Sports journalist Todd Balym posted: "Paul Gallen admits age has finally caught up with him in boxing… four rounds later he fully won over the crowd. Great fight. Gotta respect his courage. Toughest man in Australian sport. But it's time to retire".
Round by round scores — Terzievski puts on a masterclass
Round 1 — Kris Terzievski has shocked the Newcastle Entertainment Centre by keeping Paul Gallen at bay with some telling body shots. Terzievski used his superior reach and managed to keep Gallen outside.
Round 2 — Paul Gallen has worked his way into the fight. The former NRL player had the better of the exchanges in the second round. He also landed a heavy right hook.
Round 3 — Terzievski has been able to control the fight and has thrown Gallen off his gameplan of coming forward with a barrage of body shots. Gallen just hasn't found a way to get into his opponent's face.
Round 4 — Terzievski is all over Paul Gallen. The gangly southpaw has landed a flurry of body shots that appears to have taken the steam out of Gallen's attack. Terzievski also landed a clean left hand down the middle. Terzievski was warned by the referee during the round about pushing against his opponent.
Round 5 — Paul Gallen may be down 5-0 as Kris Terzievski continues to land shots with his superior reach. The body shots appear to have left Gallen with almost nothing left in the tank. Aussie boxing legend Jeff Fenech said on Main Event: "He's looking tired".
Round 6 — Paul Gallen appears to be without answers as Terzievski keeps him beyond arms length. Gallen's guard repeatedly dropped down as a result of fatigue. Jeff Fenech said: "He's stuck in a rut at the moment. His feet are heavy. He's tired".
Round 7 — Terzievski is penalised a point after a third warning for pushing against Gallen. Gallen has one of his better rounds but the round could have gone either way. Ben Damon said on Main Event: "There were signs in that round that he (Gallen) can get to him".
Round 8 — Gallen is rocked. Gallen is momentarily stunned but Terzievski is unable to take advantage. Terzievski is also showing signs of extreme fatigue.
Round 9 — The crowd has gone nuts as Gallen presses forward and lands some shots. Terzievski is in trouble and was on wobbly feet before surviving to the bell. Ben Damon said: "Terzievski can barely sit down".
Round 10 — Gallen chases his dancing opponent without much success. The final round is rocked by a series of glove failures for Terzievski with his tape repeatedly coming loose. Aussie legend Jeff Fenech said Terzievski should have had a further point deducted.