Thunder’s two-man game works for now, but what about playoffs?

They make the incredible look so routine, Kevin Durant flipping up crazy shots that somehow go in and Russell Westbrook wildly contorting his body on blow-by-everyone drives to the basket.

The show goes on for the circus that is the Oklahoma City Thunder, even without its third ring.

James Harden has taken his supernatural talents to Houston, leaving behind a juggling act for his former teammates.

The numbers are still crowd pleasers. Oklahoma City leads the NBA in scoring at 106.7 points per game going into Sunday’s game against the Clippers at Staples Center and has the same 42-16 record it had at this point last season on the way to the Finals.

It’s just that some wonder if the Thunder can induce enough oohs and aahs when it’s time to perform under the big top of the postseason.

“I think the loss of Harden will become huge in the playoffs,” said TNT analyst Steve Kerr, a former general manager of the Phoenix Suns. “I think it becomes a much bigger issue when you’re playing better teams consistently on a nightly basis.”

Harden, last season’s NBA sixth man of the year, was a main attraction for the Thunder in last season’s Western Conference finals. The shooting guard came off the bench to score 12 of his 20 points in the fourth quarter of a Game 5 victory on the road against San Antonio, making the late three-pointer that swung a tied series in Oklahoma City’s direction.

Could the Thunder be walking a playoff tightrope without the dynamic talent that Kerr called “probably its best one-on-one player”?

“A lot of people say that,” Durant said. “I don’t want to be arrogant or nothing, but I think I can fill that void. I can put the ball in the basket. That’s what I was born to do.

“Some nights they need me to do that, some nights we don’t need me to do that. But when the time comes, Coach [Scott Brooks] is going to call my number and I’ve been practicing my whole life to come through. So we’ll see what happens.”

Betting against Durant is usually a losing proposition.

The lanky forward who is averaging 28.5 points could lead the league in scoring for a fourth consecutive season, but he is hardly a rote scorer. He is averaging career highs in assists (4.6), steals (1.5) and blocks (1.2) while on pace to become the second player in NBA history besides Larry Bird to average at least 28 points while shooting better than 90% from the free-throw line, 50% from the field and 40% from three-point range.

“He’s a 7-footer who pretty much plays like a two-guard,” Denver forward Andre Iguodala said of Durant, who is actually 6 feet 9, “and he’s so young that he’s still expanding his game.”

Westbrook is also experiencing a stylistic shift, averaging 7.8 assists in addition to his 23.3 points per game. Last season, the former UCLA point guard averaged only 5.5 assists.

“Instead of having three guys who love the ball in their hands, now we really have two,” said Thunder guard Kevin Martin, who has assumed Harden’s role as sixth man after coming over from Houston in the October trade that reflected the financial realities of Oklahoma City’s small-market status.

Whereas Harden thrived running the offense, Martin plays more off the ball, relying on cuts and screens to generate points.

He has helped offset the loss of Harden’s 16.8 points per game from last season as the Thunder has taken a somewhat more team-oriented approach. Durant’s and Westbrook’s shot attempts are slightly down from a year ago in part because of step-up performances from Martin (14.6 ppg) and forward Serge Ibaka (13.6).

“As we gain experience,” Brooks said, “we’re going to find different ways to score and I think that’s been the natural progression of our group individually and collectively as a team.”

That’s not to say the Thunder hasn’t stumbled, particularly when it comes to the second unit.

A primarily reserve corps of Martin, Reggie Jackson, new addition Derek Fisher and forwards Ibaka and Nick Collison was on the floor in the second quarter Friday at Denver when the Nuggets assumed control of a game they eventually won, 105-103.

Oklahoma City’s bench was outscored, 71-11, by its Denver counterparts, highlighting the potential pitfalls of life without Harden. The Thunder recently tried to bolster its second unit by acquiring defensive stopper Ronnie Brewer and Fisher, the savvy 38-year-old veteran and former Laker whose locker-room presence may supersede his on-court value at this point in his career.

“Even though statistically I think they’re getting an identity,” Nuggets Coach George Karl said of the Thunder’s reserves, “I don’t think they’re getting that winning identity that comes with [Harden]. I mean, last year when they went to their bench you were sometimes afraid of that more than you were the first unit.”

Of course, only sporadic production may be needed from the bench when you have the NBA’s highest-scoring duo. Durant and Westbrook average a combined 51.8 points and have splurged for as many as 83 in a game this season.

“We have two superstars that make the game easier for everybody and can carry the load,” Martin said.

It’s worked for the season’s first four months.

Whether it carries over to April, May and June remains the ultimate test.

“We can talk about how many points they’re scoring and how many games they’ve won,” Kerr said. “Literally none of it matters because the franchise is at a place where they’ve gotten so good the bar has been raised to, now you have to win the title and that’s the only thing that really counts. How they fare in the playoffs is really the true measurement.”

That’s when the Thunder will learn if two ringleaders are enough.

ben.bolch@latimes.com

Twitter: @latbbolch