Was Sunday’s Celtics blowout, as Chris Bosh suggested, “just a bad, sh#tty game” by his Heat, or was it a warning signal to potential playoff opponents flashed from Boston — one if by C’s, so to speak?

On their way to producing the NBA’s second-best record since the All-Star break, the Celtics have won five straight and seven of their last eight games, the most recent of which handed Miami its third loss in five contests. Over the past week, Doc Rivers & Co. have surged from the Eastern Conference’s seventh seed to within 1.5 games of Dwight Howard‘s Magic and the No. 3 slot. Count the Heat among those in the league taking notice.

“I’m going to say the same thing I said last year: We are one team and I am one guy that never counts the C’s out,” said NBA MVP favorite LeBron James. “I would never count them out. They’ve just got too many winners. They’ve got guys who have been in the moment before. Like I told you guys last year, when everyone was down on the C’s, I always said I’m not going to turn my back on those guys.”

Of course, those guys James referred to are Kevin Garnett, Paul Pierce, Rajon Rondo and Ray Allen, the latter of whom missed his sixth straight game on Sunday. Didn’t matter, thanks to Avery Bradley and Brandon Bass.

“It’s because we’re a great team,” said Garnett following their 91-72 win over the Heat on national television. “Our positions and personnel, it’s all about a system. You know your role in the system. You do what you’re told in the role. You carry out your role 100 percent wholeheartedly, and that’s your contribution to the team.”

Heat superstars Dwyane Wade and LeBron James are well aware of the Celtics' championship pedigree. (AP)

That’s how the Celtics have been able to plug in players like Bradley, Bass, Greg Stiemsma, Sasha Pavlovic and Keyon Dooling, among others, and continue to build a cohesive unit.

“We have a team that is really about us and what we do, building habits and building for the playoffs,” said Dooling after Friday’s victory against the Jazz. “This team is made for the playoffs. It’s built for grind-it-out type games, and that’s usually how playoff games are, so we’re building our habits, guys are executing their roles and starting to get better.”

Remarkably, eight of the 12 players that lost the Eastern Conference semifinals in five games to the Heat last season are no longer on the C’s active roster. Only the core four remain. In other words, this is an entirely different Celtics team — one that as a result of the NBA lockout and a rash of injuries has had to learn on the fly without much practice time.

“This season has been in disarray and obviously not one that we love, but we’ve acclimated to it, man,” added Garnett. “We’ve been able to make the adjustments to it. Like I said, we’re taking it one game at a time. We’re playing hard as hell. We’re all joined by one, and we’re picking each other up where others lack. That’s what it is.”

With the exceptions of Shane Battier and Norris Cole, both upgrades off the bench who have played significant minutes from the start of this season, Miami’s rotation remains largely the same as last season. Same goes for the Bulls. Meanwhile, the Celtics have quietly patched together the NBA’s best passing team offensively (23.6 assists per game) and the league’s top defense in terms of field goal percentage allowed (opponents shooting 42.0%).

“They’ve got a good team,” said James in the aftermath of his team’s worst scoring output in two years. “No matter who’s out on the floor, when they have those guys who have been in the moment everybody else picks it up.”

Garnett’s move to center, Bradley’s evolution and the addition of Bass have made these Celtics a different dragon, trained against the Wizards and Bobcats of the world and unleashed Sunday for a nationally televised audience.

“It may give other people confidence in us, but I think our guys are a pretty confident group,” said Rivers. “They feel they can play with anyone. We also know we have to get better at a lot of things, too, while we’re doing that. We’re a team that, to me, is still trending up, and that’s a good thing.”

Sure enough, Rivers must figure out how to balance Allen’s return to the offense with Bradley’s impact on both ends, see what he can elicit from Ryan Hollins and wait for a verdict on the future of Mickael Pietrus. All could benefit the Celtics going forward, or they might be forced to go to battle with the lineup that took the floor on Sunday — a group that posted a better record in March than any unit since the 2007-08 Celtics.

“We know we can play with the best, and I think as of late we are starting to come together at this point in the season, knowing that the playoffs are right around the corner,” said Pierce. “We are starting to hit our stride at the right time, ever since the All-Star break, and now coming down the stretch we’ve won a lot of big games.”

All that said, perhaps the biggest difference between these Celtics and the team that finished the 2010-11 season is a healthy Rondo, who with two working elbows became the first player since Steve Nash seven years ago to record 10-plus assists in 13 straight games or at least 11 dimes in 11 consecutive contests.

“When we have at least four or five guys that are healthy, we follow the game plan,” said the 26-year-old point guard, “but when I’m healthy, I think we can probably beat anybody.”

First, the Celtics must finish out the remainder of the regular season, a brutal stretch beginning Wednesday of 14 games in 23 days that includes 11 games against playoff contenders, a back-to-back-back and two more meetings with Miami (April 10 and 24). In a month’s time, these C’s could look like the team that finished February with a 17-17 record and appeared bound for a first-round playoff exit, but the Heat certainly aren’t counting on that.

“Look, man, no one in this locker room counted the Celtics out,” said Battier. “You know they’re going to be there come April and May. They’re just two well coached and too disciplined, so we play them two more times, and we hope to keep improving against them.”

“We still have to play them again,” added Rondo. “It’ll be a brand new 48 minutes, so it’s one win. We’re going to take each win in stride, but other than that we’re trying to go a win at a time.”

If the C’s add up enough of those wins, they just might be headed for an Eastern Conference semifinals rematch with the Heat. Only this time it will be a different Celtics team that takes the floor.

(Have a question, concern or conception for tomorrow’s Irish Coffee? Send a message to @brohrbach on Twitter.)