This home-and-home series against the Senators was surely circled on the Joseph family's calendar at the start of the year. It would mark the first time that 25-year-old Mathieu and 23-year-old P.O would play against each other at the NHL level.
"As a kid, both of us playing downstairs in the basement, and both of us being able to reach this level together is a game I'll remember for the rest of my life," Mathieu told me after the Senators' morning skate on Friday.
Really, what happened on Friday shouldn't have come as a surprise. The brothers have played each other many times at lower levels -- 11 times in junior in the QMJHL, and then once in the AHL. When I asked P.O on Tuesday about his recollections of those games earlier in the week, he broke into a little grin.
"We always get penalties against each other," P.O said. "We love each other before the game, then hate each other after the game because we just compete against each other so hard. I feel like we know that when you go into the corner against your brother, you have to go a little harder. It's fun. It just keeps us pushing each other, really."
In a win for younger siblings everywhere, P.O and the Penguins managed to come out on top with a 4-1 win in this first NHL meeting between the Joseph brothers. Not only did he get the win -- but he managed to get his big brother in a little trouble, too.
There were just under seven minutes remaining in the third period when P.O played the puck in the corner, and Mathieu went to lay a hit. P.O elevated his stick as he followed through with the pass and inadvertently high-sticked his brother in the face. P.O got hit in the face himself in the collision, and both brothers ended up in the penalty box for matching high-sticking minors.
The problem with the calls, though, was that Mathieu wasn't the one to hit P.O in the face. P.O hit himself in the face with his own stick. Referee Kelly Sutherland had his back turned when the collision happened, and seemed to just be judging by the reaction of both players grabbing for their faces:
"It's classic that we take a penalty against each other," P.O said afterward. "But I think my own stick got me in the face, and I didn't want to say anything. I felt bad for having a penalty, but it was a good thing it was a 4-on-4."
You could see the brothers yelling back and forth to each other from their respective penalty boxes, and I asked P.O afterward what they were saying to each other in that moment, and he said that he had immediately fessed up to what happened.
"I told him that it was my own stick somehow," P.O said with a little chuckle.
Mathieu didn't find the ordeal quite as funny.
"That was not a penalty on me," Mathieu said. "So, I don't really know what happened there. I think he got his own stick in the face, I just got caught up in there. I don't know if they thought it was going to be funny or something that we both got a penalty at the same time, but stuff happens. I'm sure my parents had a good laugh about it, but I didn't think it was funny."
Their parents, who made the nine-hour drive from their home just outside of Montreal for the game, definitely were amused by it all. The television broadcast cut to their father Frantzi shaking his head with his hands in the air while mother France tried to stifle a laugh:
Both P.O and Mathieu said before the game that their mother gives them one rule for these games -- no fighting. P.O sounded pretty confident that high-sticking his brother (and himself) was within the boundaries of the rule.
"Every league we play against each other we have a penalty against each other," P.O said. "I guess she figured it was going to come at some point."

PENGUINS
Mathieu and P.O Joseph in warmups on Friday at PPG Paints Arena.
France told me during warmups Friday that she had this image in her head of a 2-year-old Mathieu with two mini-sticks in hand, excited to get a game going with his little brother, who was only three days old at the time. Mathieu was disappointed when he realized that P.O was still too little to play with him, and that he'd have to wait a few more years until they could play together.
Even though Mathieu wasn't too happy with the way this game played out, he still said that it was a dream come true to be able to play at the highest level against his little brother, after growing up playing with those mini-sticks in their basement.
"It was awesome," Mathieu said. 'It's good to see my little bro over there doing his thing, and I thought he had a really good game too. It's a childhood dream for us. Since we were playing hockey, dreaming of playing in the NHL and playing with some of the guys that we have on the ice with us tonight. It was a dream come true to be able to play together on the same ice at the same time at this level. I'm sure my parents are proud."
With Mathieu in his fifth NHL season and P.O solidifying his role a a full-time NHL player this season, these matchups between the two brothers will surely become commonplace in the future. One would imagine that next time, Mathieu will be all the more motivated to make sure he doesn't get shown up by his little brother twice in a row.