BOSTON -- When Kevin Garnett returned to Boston in January to play his former team for the first time, he was overcome by emotion, particularly during a video tribute that the Boston Celtics put together. After that game, a nostalgic Garnett lodged one tiny complaint: He could have used some Gino.

For the uninitiated, there’s an old “American Bandstand” clip that the Celtics run on the JumboTron at the tail end of lopsided wins as The Bee Gees’ “You Should Be Dancing” blares. Garnett helped the clip grow to cult status during the Big Three era and often pointed skyward when a smooth-grooving man in a Gino Vannelli T-shirt appeared, which helps explain how it came to be known as Gino Time.

Garnett got his wish on Wednesday night -- sort of. The Gino Time clip rolled with just under three minutes to play as the supposed-to-be-rebuilding Celtics polished off a 121-105 triumph over Garnett’s Brooklyn Nets at TD Garden.

“Listen, I was so upset I didn’t even get the really, really deep Gino in my system,” Garnett said. “My low moment for the night, you know what I mean? Gino is a big part of me and I didn’t even get to celebrate it. I’m still a huge Gino fan.”

He’s maybe even still a bit of a Celtics fan, at least as much of one as a division rival can be. Garnett gushed about his former squad, including the schemes second-year coach Brad Stevens threw at the Nets, the way rookie Marcus Smart defended, and especially how his little buddy Rajon Rondo performed while returning to game action less than five weeks after having hand surgery.

Kevin Garnett, who could do little to slow Avery Bradley and the Celtics, came away very impressed with his former team. AP Photo/Elise Amendola

Garnett even suggested that he’s eager to watch some Celtics games this season. That is particularly astounding considering that some Boston fans were not even eager to watch this team play. At least not before Wednesday.

But the Celtics opened the 2014-15 season with the sort of fireworks that the offseason lacked, absolutely dominating the first half with nothing but defense and grit, all while a once-anemic offense blistered the floor by shooting 61.4 percent. Boston led by 26 at intermission.

At the center of it all was Rondo, who went from being a nap-time decision to flirting with the 30th triple-double of his career. The 28-year-old point guard finished with 13 points, 12 assists and 7 rebounds in just under 30 minutes of action, then suggested he was playing at only 91 percent.

And yet he was just one of eight Celtics players in double figures as Boston embraced the unselfish approach that Stevens yearns for. Wednesday’s game offered a glimpse of the team’s potential when everything clicks.

The second half wasn’t nearly as crisp, and Stevens made sure to remind his troops that there’s an awful lot of room for growth. But the Celtics were so dominant early on, it allowed them to downshift at times over the final two quarters.

“I thought our intensity was really good, even when we were scrambling and out of sorts, we were doing it hard,” Stevens said of the stretch in the second quarter when Boston took control of the game. “We were flying all over the place, we were active, we were active to the biggest threats. They missed some open 3s, but I thought that we really played [well] in the first half defensively.

“It’s hard to be up 26 and continue to play that way and you saw -- I thought the start of the third quarter we were much, much, much less authoritative in our defensive stance -- so we’ve got to grow from that and it’s a great game for us because I thought we did a lot of good things. We can build off those, but we can get a lot better, and we showed that too.”

The Celtics had high hopes for their defense this season, but the offensive barrage was downright staggering. The Celtics ranked 27th in offensive rating last season, averaging a measly 99.7 points per 100 possessions. They were 25th in assist-to-turnover ratio, 28th in both efficiency field goal percentage and true shooting percentage.

So the sight of 67 points at halftime, and triple figures when Kelly Olynyk made an off-balance baseline jumper to end the third quarter, left even the most optimistic Celtics fan shaking his head. The Celtics shot 55.7 percent, turned the ball over just 13 times and generated a whopping 62 points in the paint, this after living off the 3-pointer for much of the exhibition season.

As Garnett would say in defeat, “You don’t win anything on the first night.” And that’s a sentiment that Stevens will repeat to his team often over the next 48 hours.

The Celtics are set to embark on an extremely challenging November, a month that will tell us if Wednesday’s game was a fluke or a sign that Boston -- with a healthy Rondo, an improving young core and a more experienced Stevens -- has the ability to take a real step forward this season.