Well, well, well, what have we here? The Boston Celtics have made it to the second round of the NBA playoffs for the second year in a row.

For a proud franchise like the Celtics — winner of a league-record 16 world championships — the fact that this back-to-back feat was accomplished for the first time in 11 years is hardly worth trumpeting. Nevertheless, while the Rick Pitino era does seem like a distant memory, the 2002-’03 team’s achievement is unquestionably helping to flush the memories of that dismal six-year stretch when the C’s failed to make the playoffs under the leadership of Chris Ford, ML Carr, and Pitino.

Even better for Celtics fans, this year’s squad has managed to confound the prognosticators and rise from the ashes, emerging from the sixth seed to advance to the second round by virtue of its impressive four-games-to-two dismantling of the third-seeded Indiana Pacers. When you start as sixth out of eight conference-playoff teams, expectations are reduced, not only because of the caliber of the opposition, but also because you lack the home-court advantage for four games of the best-of-seven series. The relative ease with which Boston advanced, then, is certainly noteworthy.

Boston Globe columnist Bob Ryan — a long-time Celtics follower, chronicler, historian, author, and one-time beat reporter — pretty much wrote off Boston’s chances against Indy prior to the series, but once the Green stole game one against the Pacers at Conseco Fieldhouse, hope re-emerged for the once-doubting Celtics followers. Boston not surprisingly lost game two to a fired-up Indiana team, but the Isiah Thomas–led Pacers were no match for the home-court that was the FleetCenter in the three games played in Boston. The Celts were competitive in two of the three road contests in the series, and if not for throwing a shutout in overtime in Indy’s 93-88 home win on Tuesday — a game in which Boston led for approximately 95 percent of the contest — this series might have been over in five games, affording the team an additional break before taking on the Nets in the conference semifinals.

Nonetheless, the passion with which the Celtics played this series, and the means by which the Pacers were most confounded — balanced scoring among the top six players on the team, rather than by significant contributions from Antoine Walker and Paul Pierce and marginal assistance from the other 10 — were what led to the surprising effortlessness with which Boston handled the talented Pacers.

Of course, there was the other X factor: coaching. Jim O’Brien has shown himself to be one of the top coaches in the NBA, even though he not so long ago seemed stuck on the career path of either a) following Pitino around as a loyal assistant wherever the former Kentucky coach’s myriad travels took him; or b) spending the bulk of his days coaching at various collegiate venues such as Oregon, St. Joseph’s, Maryland, Pembroke State, and Wheeling Jesuit College (West Virginia), where he first built his reputation in the coaching ranks. Fortunately for O’Brien, Pitino resigned abruptly in January 2001, and his top assistant finally got the opportunity to show his chops at the NBA level. He took over a team that had long been mailing it in (to the tune of a 12-22 record) and led it to a respectable 24-24 log during the balance of that 2000-’01 season.

Since then, O’Brien and his able coaching staff have nearly returned the team to the lofty heights to which the Boston hoops fandom had become accustomed during the successful stewardships of Red Auerbach, Bill Russell, Tom Heinsohn, Bill Fitch, and KC Jones (save for the occasional NBA title). Last year, the team went 49-33 during the regular season and advanced all the way to the Eastern Conference finals before bowing in six games to the Nets; this year, the team — despite losing a number of key components of last year’s playoff contingent — went 44-38 and never fell out of playoff contention despite the non-factor that was Vin Baker and the fact that the team was three-pointer-obsessed and excessively reliant on Pierce and Walker’s potential for heroics.

Indiana certainly contributed to its own demise in the playoffs. The team stumbled to an 11-19 record to close out the season, and its ability to mesh suffered from overbearing egos. The Pacers shot only 39 percent from the floor (181-466) during the series, and just 29 percent from three-point range (31-106). Boston’s ability to hit the threes (hitting 38 percent from beyond the arc) was a key factor in its series victory, but the contributions of Tony Delk (15.5 points per game) and Walter McCarty (12.5 ppg), along with the efforts of the dynamic duo, were decisive. Twice, the team overcame 16-point third-quarter deficits and emerged victorious.

Many figured Pierce and Walker — both of whom have been hampered by injuries during the course of the regular season — would have run out of gas by now, but the play of the reserves has allowed them some significant downtime on the bench. Like last year, the two have elevated their intensity to supersonic levels during playoff time, and the co-captains continue to lead their comrades by example.

Not too many figure that the Celtics can achieve the same kind of success against the Nets in the next round, especially since New Jersey took three out of its last four regular-season meetings by considerable margins (117-81, 90-75, 87-74). On paper, the second-seeded defending East champs would seem to have more weapons and depth than the Celtics.

However, the Nets certainly face some danger in their upcoming match-up with Boston. Many thought the Pacers had wanted to play the Celtics in the first round, rather than the potential landmines they had hoped to avoid in New Orleans, Orlando, and Milwaukee (teams that they figured posed more problems because of their across-the-board talent).

Boston nonetheless has a chance, as long as O’Brien can manage to out-coach counterpart Byron Scott (another former standout as a player who has achieved more success on the bench than Thomas — with his three consecutive first-round losses — has thus far). The defense-minded Celtics also need guys like McCarty, Delk, Eric Williams, and J.R. Bremer to make the open shots when the consistently double-teamed Walker and Pierce have to pass the ball out.

Whatever happens in this upcoming round, Celtics fans for the second-straight year can take heart in the team’s spirit and relentless pursuit of success. The steady hand of O’Brien and the mercurial efforts of Pierce and Walker have played a big part in that. But whatever the reason, there’s little doubt that the Boston Celtics franchise has put aside the doldrums of the ’90s and taken the necessary steps to rejoin the NBA elite.

Outside Boston, few teams are hated more by the general populace of NBA fans than the Celtics. But right here, right now, this is a team that is easy to embrace, fun to root for and watch, and one that can never be counted out.

Sporting Eye runs Mondays and Fridays at BostonPhoenix.com. Christopher Young can be reached at cyoung[a]phx.com