Spurs and Celtics. Just let it roll off your tongue.

It’s never been a rivalry per se because, sadly, the two have never met in an NBA finals. It is, however, a juxtaposition of two franchises that have, if we may say so, both accomplishment and class. In an age of SUPER-teams, these franchises have built super-TEAMS. To coin a word we’ve used before, they have teamness.

(We’d add the Golden State Warriors to this mix. The Warriors built a championship culture pre-Kevin Durant — it’s one of the reasons he went there — without a single top 5 pick or major free agent in the starting lineup. Sports Illustrated’s Lee Jenkins aptly described how the Warriors are not just built on splashy shooting in his piece, “The Warriors’ Deadly Combo Of Hustle And Flow.”)

Spurs, Celtics, and teamness

Basketball is a great mystery. You can have the perfect mix of talent and the best system of offense in the game…. But if the players don’t have the sense of oneness as a group your efforts won’t pay off. — Phil Jackson

By teamness, we refer to all sorts of things.

On court chemistry: a lot of passing, a lot of ball movement… dunks and great 3-point looks. The Warriors lead the NBA in one measure of this: share field goals assisted, with an assist rate of 0.699. The Spurs are in fourth place, however, at 0.614, and the Celtics, fifth at 0.605. (The Celtics are also rising over the last 5 games, following Al Horford’s cri de couer for the team’s offense to return to “beautiful basketball.”)

If you look at things like scoring distribution, minutes played, defensive effort (or declining minutes if this is lacking)… you get a similar picture for both teams.

Roster building: Drafting, trading, development, and, even when it comes to free agency, finding under-valued assets as opposed to top-5 or top-10 players at the time. The Spurs did so this offseason with Rudy Gay; the Celtics picked up former Spur Aron Baynes over the summer in one of the NBA’s most under-rated acquisitions.

Hustle: The Celtics rank second in the NBA in the NBA’s aggregated hustle measurement. (They’re number one when you incorporate a stat we’re launching on our own, the “rebound assist.” More on that soon.) The slower, veteran Spurs are uncharacteristically low by this metric, but they’re in the leagues top 10 in deflections, loose ball recoveries, and charges drawn. (The first two are areas where the Celtics need improvement, by the way.)

Discipline: San Antonio, as is common, is near the bottom (second) of the league in drawing technical fouls (second lowest, at 0.2 per game). LeBron James made news earlier this season when he earned the first ejection of his career. Kawhi Leonard made news last season when he drew his first technical foul ever.

Eyes on the prize: This is hard to quantify, but both the Celtics and Spurs tend to deflect conversation about individual awards, honors, and even game-by-game results. Even the fan bases are relatively less inclined to care about individual honors. “There’s only one goal for the Boston Celtics,” as Jaylen Brown put it last year.

All this is in keeping with the ethos built by Red Auerbach, and carried forward by Danny Ainge, Paul Pierce, Brad Stevens, and others: “The Boston Celtics are not a basketball team, they are a way of life.”

Tonight’s Celtics vs. Spurs

Red Auerbach also said: “You don’t win games as a coach during games. You win games as a coach before games. Players win during games, not coaches.”

With that in mind, here are three keys to tonight’s clash of the Teamness Titans.

1. On defense: Contest and harass Rudy Gay and Patty Mills, and encourage David Aldridge to settle for those contested 15-foot fadeaways that he likes. The Spurs are a streaky shooting team both between games and in games. Though a veteran squad, they will also turn the ball over when confronted with young greyhound feet and hands like those the Celtics present.

2. Continue beautiful offense sometimes run through “Point Horford,” sometimes Kyrie, sometimes, Jaylen Brown slashing and Jayson Tatum smooting. Marcus Smart just needs to keep shooting, and making more. The Celtics are surging in team dunks off cuts ever since Horford’s “beautiful” aside. So far so good.

3. The return of Dr. Jaylen Brown. Celtics fans are hoping for Brown’s return (and health) after a one-game absence with an eye infection. It’s “the mask and the goggles” Friday for the Boston Celtics… 2-point underdogs as they travel to San Antonio.