And through the decades there was one Causeway Street moment that stood out above the rest: Bobby Orr's iconic Stanley Cup-winning goal on May 10, 1970, of course.

That was until his son came around. Orr's goal slid to No. 2 after Matt Grzelcyk's overtime winner for Boston University in the 2015 Beanpot final against Northeastern. On Friday afternoon, Orr dropped down another notch.

Matt Grzelcyk gave his family plenty to celebrate when he grabbed his first career goal in the Bruins' 4-3 victory over the Pittsburgh Penguins, which was the B's fourth consecutive win and moved them into third place in the Atlantic Division.

"It's going in a mantle piece probably up there with the goal he scored against Northeastern to win the Beanpot. The first NHL goal goes right up there with that," John Grzelcyk said after receiving the puck from Matt following the game. "Bobby Orr's goal has moved down to three. It was two - it was one - but then he scored in the Beanpot. I feel bad for Bobby Orr, but he's my son."

Video: Matt and dad John speak after Grzelcyk's first goal

John Grzelcyk was in the stands for his son's first goal, but it was not a complete day off for the longtime member of the Bull Gang. The annual Black Friday doubleheader meant a quick changeover was needed before the Celtics' 7:30 tip-off against the Orlando Magic.

That did not, however, take away from what became such a special day for the Charlestown natives.

"When he gets a goal with all the hard work he's done to get up here at this level and these great players…it's something you can't take away. It's on the record. It was awesome," said John Grzelcyk.

Video: PIT@BOS: Grzelcyk nets first NHL goal from the dot

The younger Grzelcyk has played in two games for the Bruins since his recall from Providence on Tuesday and has acquitted himself well during what is now his third stint with the big club over the last two seasons.

The 23-year-old former Boston University standout grabbed his first career point with an assist on Jake DeBrusk's goal against the Devils on Wednesday night, before posting a plus-2 rating in nearly 12 minutes of ice time against Pittsburgh.

"Adding Grizz into the mix does give you another puck mover with Charlie [McAvoy] and [Torey] Krug if all three are in there," said Bruins head coach Bruce Cassidy. "I think that's important. And that's not being disrespectful to the others…we are finding that balance. And I think it's something that we'll tinker with for a while, and the more Grizz plays consistent hockey, the easier the decision it makes."

Grzelcyk has often been compared to Krug - who returned to the lineup after a three-game absence against the Penguins - in skill set and stature, with both players standing at 5-foot-9.

"We have a playmaker on each pairing now and we can move the puck and it get it into the forwards hands, and if you're breaking the puck out and you're not defending then you don't need to worry about the size of your guys out there," said Krug, who landed three shots on goal in a tad over 18 minutes of ice time in his return. "Grizz will find his way. He played a heck of a game out there today."

Video: Krejci, Pastrnak propel Bruins to 4-3 victory

That he did. With Boston clinging to a 2-1 lead midway through the second period, Grzelcyk struck for his first. Following a David Krejci faceoff win back to Kevan Miller at the right point, Miller found DeBrusk (two assists) along the half wall. DeBrusk then fed Krejci (goal, assist) in the slot, where the pivot whiffed on his one-timer attempt.

The puck skittered to Grzelcyk, who ripped a wrister from the bottom of the left circle off Matt Murray's glove and into the net for a 3-1 Bruins advantage at 10:31 of the middle frame.

"Right before, JD told me to go backdoor, so I was heading that way and Krech came over right after actually and said 'Well, don't go down all the way. Wait in the slot,'" said Grzelcyk. "Just kind of fate happened and he fanned on the puck and it landed right on my tape. Credit those guys for putting me in the right direction."

The 2012 third-round pick became the seventh Bruin to tally his first career goal this season, joining Anders Bjork, Peter Cehlarik, DeBrusk, Danton Heinen, Sean Kuraly, and Charlie McAvoy.

"Yeah it was pretty special, obviously. It brings back memories skating as a kid and stuff like that. It hasn't really set in yet. It was pretty cool to get that out of the way," said Grzelcyk. "It was kind of a jolt through my system. I didn't really know what was going on I was trying to hide it the best I could. I think the rest of the guys were trying to make me smile. I was really happy."

As was his dad, who is just fine with continuing to push No. 4 down the list.

"It was a great family day, yesterday was a great family day with Thanksgiving," said John Grzelcyk. "This was just a continuance. Hopefully there's more down the line."