Matthew Tkachuk readily admits the passing of recent years have perhaps irrevocably tipped the physical-advantage scales in favour of his two-year-younger sibling.
"Now? No way. He'd kick my a--."
Sunday at Canadian Tire Centre, the Tkachuk boys collide in an organized game of shinny (officials, full equipment, timer, etc.) for the first time ever, at any level.
It should be a dandy when the Flames and Ottawa Senators - and the brothers Tkachuk - take to the ice against each other.
"Other than playing in the driveway every day growing up … that's as far as it ever got,'' recalls Matthew.
"We used to have this big driveway at our old house, make two nets on each side, me versus my brother and my sister (Taryn). My and brother I had to hit the post, my sister just had to score.
"From a competitive perspective we've played against each other in everything imaginable.
"Literally anything you can think of."
But never hockey?
"Never hockey, no.
"Not in a game situation.
"So it'll be real fun."
They are, of course, two of the most eye-catching young standouts to be found anywhere across the NHL spectrum: Matthew, the sixth-overall pick from the 2016 draft by the Flames, Brady the fourth-overall selection by the Sens last summer.
Big brother is in the midst of his finest of four NHL seasons, compiling 24 goals and 59 points already. Brady has made an undeniable impact in this, his rookie campaign, accruing 30 points in a season interrupted by a torn ligament in his left leg.
"I'm super-excited (about Sunday)," confesses 19-year-old Brady. "It's gonna be a little different, a little weird, for sure.
"To finally be playing against other, and at the highest level, is pretty cool.
"This isn't going to change the way either of us play, though. We're going to go hard. Family before and after, but inside the game you're not changing a thing.
"Obviously when Matthew got drafted I became a fan of the Flames so I've watched them quite a bit. Met a couple of the guys since he's been there. He's always been a huge role model for me but especially the last couple of years. I've learned a lot from him. Still am learning, watching him, how he takes care of himself and spending summers together.
"It should be a blast."
Video: Matthew and Brady Tkachuk on the family's big weekend
There are, naturally enough, plenty of Tkachuk kin and friends making treks, both long and short, into Kanata for Sunday's Battle of the Brothers.
"For all the people coming in, it's probably more of an event than a game," muses Matthew. "I'm sure everybody in the NHL who's played against their brother, after awhile, feels like it's just another game.
"Well, this isn't just another game.
"It's the first game. So it's a special one."
On the ice, stylistically, the two Tkachuk offspring are similar: sublime mixtures of skill and sass; lethal combinations of artistry and antagonism.
Off the ice …
"Their personalities are very different, apart from the competitive aspect," says mom Chantal. "Brady's a bit more happy-go-lucky, easygoing, but when you push him too far … we always joke when that happens his head spins three times and he turns into this alter-ego person.
"And everyone knows to stay far, far away.
"Matthew's always been a bit more on the serious side.
"But they reach out to each other often. They're very tight."
A tightness that comes across when asking one about the other.
"He's an unbelievable brother,'' says Matthew. "From a hockey perspective, the way he's been able to fit in with his team as an 18-19-year-old is great to see. Such an impressive guy. Gets along with every single person.
"He's just one of those guys everybody wants to be around. The life of the party.
"A fun-loving kid."
Right back at ya, bro.
"I'm his biggest fan," says Brady. "What makes me so proud is … everything. I just feel he does everything the right way. Wherever he goes, everybody on his team loves him.
"He's that guy we all want on our side - the guy who kinda brings everyone into the battle. You always hear the saying: Big-time game, big-time player.
"He's one of those.
"I just love watching him. He's so smart. So good with the puck. He can play whatever way you want. Always willing to go to the dirty areas and earn those bruises to make plays.
"He's not afraid of anyone."
If the prospect of the resumption of those long-ago basement/roadway/playground bickering battles has the protagonists amped, just imagine how stoked the parents are about Sunday.
"It's a real exciting opportunity to watch two boys, brothers, who grew up together as best friends play against other in their dream - the National Hockey League," says Keith, the 12-season, 1,201-game, 1,065-point power forward deluxe.
"Chantal and I are going to be really nervous, I'm sure. But this'll be great for us, my parents, my father-in-law and all the relatives who'll be there to watch.
"You can't root for anybody, of course; just hope for the best and whatever happens, happens."
Mom has figured out a fashion solution for the occasion, though: Just wear red. It fits in both camps.
"I could've never imagined that I'd be fortunate having two boys playing in a game like this,'" Chantal says, "but here we are.
"Of course it's been circled on our calendar all year."
This familial head-to-head, of course, will soon become a yearly ritual for the Tkachuk siblings.
But, as Matthew points out, there's only one first time.
"We haven't really talked much about it," admits Brady. "Earlier in the year a bit, but it always seemed a long ways away.
"Now it's right at our doorstep.
"It's going to be great, having so many people there who've had such a big influence, big impacts, in both our lives.
"I know my mom's going to be pretty emotional. She might cry once or twice. But that's OK.
"Should be good."
Good? It promises to be great.
"It's funny," muses Matthew, "but when you're younger, growing up, you're always chirping your brother, right?
"You always want to have the last word.
"He'd be chirping me and I'd always chirp him back: 'One day, I'd love to play against you. You wait. One day it'll happen.'"
That day is finally close at hand.