Say this about the NBA playoffs: It’s usually quite predictable.

Nothing wrong with that.

It’s a star-driven league built around enticing matchups. Quite frankly, the Finals will be a letdown if we don’t get the rubber match of a Cleveland-Golden State trilogy.

But there’s nothing wrong with a little drama at the start of the postseason, a bit of madness in April rather than March.

That’s why this opening week has been so compelling, with upsets galore and stellar performances all around.

Boston, the top seed in the Eastern Conference, lost the first two games on its home court to No. 8-seeded Chicago, which needed a tiebreaker to slip into the playoffs on the final night of the regular season.

But, with Rajon Rondo out indefinitely for the Bulls with a broken right thumb and the Celtics getting a pep talk from Kevin Garnett, Boston went on the road and made a series of it by winning 104-87 Friday night and 104-95 Sunday night.

“He basically said put a little more KG into it,” Jae Crowder said of Garnett’s recorded message, delivered before Friday’s game.

Third-seeded Toronto finds itself in a 2-2 spot against the moving-up-with-a-bullet Bucks, who are trying to get past the first round for the first time since 2001. Milwaukee was dominant in its Game 3 victory, overwhelming the Raptors 104-77 before a raucous crowd at the Bradley Center.

The Raptors were able to climb to even Saturday night, 87-76.

“It was just fun, fun to play with such great fans,” All-Star Bucks forward Giannis Antetokounmpo said, savoring a glimpse into a bright future.

Speaking of fun (to watch), enjoy Russell Westbrook as long as you can. He may not survive the opening round with the Thunder down three games to one, but he’s doing his best to extend one of the greatest seasons in NBA history. In a loss at Houston, he scored an astounding 51 points as part of his usual triple-double, and, we can only assume, parked cars and worked a concession stand as well.

Realizing that even he couldn’t win a game all by himself, Westbrook actually let his teammates have the ball occasionally in Game 3, spreading it around enough for a 115-113 victory. The Rockets bounced right back however on Sunday with a 113-109 win.

“I had to do a better job of trusting my teammates for 48 minutes,” Westbrook said of Friday’s game.

As if he didn’t want Westbrook to hog the spotlight, LeBron James perked up to lead the defending champion Cavaliers to the greatest second-half comeback in playoff history.

He had 41 points and a triple-double of his own Thursday night, willing Cleveland back from a 25-point halftime hole — more like a ravine — for a 3-0 lead over Indiana.

This was a foreshadowing of Sunday’s clincher 106-102 to put the Pacers out.

The Pacers have been competitive in every game, but James simply doesn’t lose at this stage of the postseason. He’s on the cusp of becoming the first player to win 21 consecutive first-round games since the current playoff format began in 1984.

Look for more familiarity once we get through the opening round.

The list of legitimate championship contenders should be fully intact, since it’s not very long to begin with. There’s James and the defending champion Cavaliers, the Stephen Curry-led Warriors and the always-in-the-mix San Antonio Spurs.

Even though Cleveland finished two games behind Boston in the Eastern Conference during the regular season, this feels a lot like two seasons ago, when Atlanta went into the playoffs as the top seed in the East.

Records notwithstanding, everyone knew the Cavaliers were the better team by the time the postseason rolled around. That’s exactly the way it played out, with Cleveland romping to a four-game sweep over the Hawks in the conference final.

If Boston and Toronto go down as well in the first round, the Cavaliers won’t face a legitimate challenger to their title until the Finals. It probably won’t matter anyway.

In a league where the cream almost always rises to the top, playoff upsets are far rarer than any of the other major professional sports.

In the NFL, the one-and-done setup means it’s always possible for an inferior team to pull off a shocker. In Major League Baseball, a favorite can suddenly go into a hitting slump or run up against dominant pitching that dooms its chances, especially in the best-of-five division series. In the NHL, a hot goalie can carry a team all the way to the Stanley Cup.

That’s simply not the case in the NBA. One or two star players — surrounded by the right supporting cast — can usually suck the air out of any upset bid, and a best-of-seven format from start to finish further ensures that the best teams are likely to wind up on top by the end of the two-month grind.

Over the last two decades, a top-seeded team has won the title 12 times. The last champion that went into the postseason positioned lower than third in its conference was the 1995 Houston Rockets — and they were defending champion.

In other words, we know who’s going to be there at the end.

Enjoy a little suspense while it lasts.