Before we begin, please join me in my pre-column ritual.

First, we repeatedly tap our heads on a basketball hoop support, preferably padded.

Next, we pour some rosin into our hands and clap it into the face of the nearest person seated.

We fist pound our enemies.

Finally, we pound ourselves in the left clavicle two or three times while yelling incoherently. Obscenities optional.

We’re ready.

Kevin Garnett made a whole bunch of people in New England happy on Saturday, when news broke that the future Hall-of-Famer had agreed to a three-year, $34 million extension with the Boston Celtics.

Garnett’s presence virtually assures the Celtics will remain viable title contenders for at least one more year. That is dependent upon health, of course. Some people might complain that Garnett’s presence also assures the Celtics will wear down by the end of the year. And there is no denying that with or without Ray Allen, they are still heavily dependent upon players who can remember when Joey Crawford had hair.

It still beats the alternative. No Garnett means a disinterested Paul Pierce, playing out the string. It means no teammate to help Doc Rivers keep Rajon Rondo’s enigmatic ego in check. It also means no one to help mentor newbies Jared Sullinger and Fab Melo into the NBA.

And let’s not even think about what the defense would turn into without its inspirational quarterback.

Garnett’s presence also assures one last reward for the man himself. Whether he plays one, two or three more years in green, Garnett’s No. 5 will live on long after he’s gone, hanging from the rafters.

Up to this point, all discussion of No. 5 joining that pantheon has come to a screeching halt with one “Yeah, but.”

Yeah, but he hasn’t played for the Celtics long enough.

If Garnett plays out his contract with the Celtics (and at $11 million, it will be a bargain regardless of how much he ages), he will have spent eight years in Boston. That’s longer than No. 22 Ed Macauley (six years) and No. 3 Dennis Johnson (seven years) and just as many as No. 31 Cedric Maxwell (although Larry Bird would argue he only actually played for seven years).

With that qualifier obliterated, some holdouts may still balk at the idea. “Yeah, but he only won one title,” will be the next station for the moving goal post, barring capture of the 18th banner in the next three years.

Championships are the measuring stick for all Celtics greats, no doubt. Macauley and Reggie Lewis are the only rafter gods without one. Lewis is an exception for obvious reasons, while Macauley was Red Auerbach’s first franchise player and helped bring a dynasty to Boston when he was traded for the draft rights to Bill Russell.

DJ and Maxwell probably wouldn’t be up there if they hadn’t won two titles during their overlapping tenures. Jim Loscutoff rode Bill Russell’s coat tails to seven titles and his number 18 was retired for another guy, Dave Cowens, before Auerbach decided to immortalize “Loscy” in letters.

Regardless of how many rings he retires with, Garnett will have had a far greater direct impact upon the franchise than Macauley, Loscy, DJ, Maxwell and perhaps as many as a half-dozen other players in the rafter club.

No one should forget how bad of a rut the franchise was in before Garnett came to Boston. Mired in an interminable cycle of one-and-done playoff cameos or low lottery draft picks, the Celtics twice tanked all or part of a season in hopes of securing the best odds at winning the lottery and rebuilding around a legitimate franchise prospect.

In 2007, when the ping pong balls bounced the wrong way for a second time, Celtics fans thought they had been sentenced to at least 10 more years of purgatory, which also virtually assured a bitter end to Pierce’s Celtics career.

After Danny Ainge acquired Ray Allen, Garnett lost his strong reservations about Boston and agreed to a trade. He immediately embraced Celtic tradition and, in his first press conference, raised the bar back to the championship level it hadn’t seen since Bird’s prime.

Garnett showed the proper amount of deference to his new All-Star teammates but he also took the lead in changing the culture of the team. On the court, it was defense, unselfishness, teamwork and swagger. Off the court, it was “ubuntu,” a team slogan and philosophy discovered by Doc Rivers but exemplified and enforced by Garnett.

He carried those standards through an MVP-caliber season ending in the first banner in 22 years, a near-miss in 2010 and an incredible run last season led by his unexpected rejuvenation.

If reports of his contract terms are accurate, Garnett’s $10 million pay cut is the latest example. He would have been justified to consider than an insult from the franchise he resurrected. He could have commanded more on the open market. Instead, Ainge now can attract an impact free agent with the full mid-level exception thanks to the discount Garnett has accepted.

In the last 20 years, no player who has put on the uniform has been a truer Celtic, and that includes the current captain in No. 34.

It’s a given that that number will hang from the rafters someday. On Saturday, Kevin Garnett guaranteed that No. 5 will hang there, too.