It took nearly three full quarters Saturday for the Liberty to go on the kind of run a superteam is supposed to produce — six points in a 45-second burst — and that’s what they used to flip a one-point deficit into a five-point lead and eventually an 81-65 victory over the Connecticut Sun.

Courtney Vandersloot started it off, collecting a one-handed pass and giving the Liberty a 46-45 lead with 3:58 left in the third quarter.

Then, Breanna Stewart forced a turnover and threaded a pass to Sabrina Ionescu in transition.

Finally, Vandersloot, who finished with 18 points and 10 assists, converted another layup, prompting a Connecticut timeout with 3:12 to go.

That was part of a 12-2 run that erased a six-point halftime deficit and helped hand the reigning WNBA runners-up their first loss of the season in front of 7,102 at Barclays Center.

That run made the Liberty’s 16-point win seem way simpler than it actually was.

Stewart only scored two points on two shots in the opening quarter, but she still led the Liberty (2-1) with 21 points as an encore to her franchise-record 45 from last Sunday.

The Liberty only went 1-for-5 on 3-pointers in the opening 20 minutes, but they still finished with nine treys.

Nevertheless, just three games into the season, the superteam earned a victory against one of the WNBA’s most consistent teams.

“The beauty of a veteran team, experienced team: we can make adjustments,” Liberty head coach Sandy Brondello said, “and they can obviously do what we’re telling them to do.”

Following that third-quarter timeout by the Sun, Stefanie Dolson sent a pass to Stewart for a 3-pointer.

Stewart capped the Liberty’s next possession with a make from beyond the arc, too.

The run carried over into the fourth quarter when the Liberty outscored the Sun by 10, and helped the Liberty erase their early mistakes on offense: Passes were deflected and possessions came up empty.

After the Liberty took a 5-2 lead, the Sun scored 12 of the next 14 points.

Brondello thought the Liberty were “sleeping in the first half.”

“It felt kind of familiar,” Vandersloot said. “Our spacing and just our inability to score felt very familiar to Game 1 [against the Mystics], and the difference was that we came out and made adjustments and moved the ball a little bit better.”

This might have been the toughest test, on paper, the new-look Liberty have faced.

The Sun (3-1) clinched playoff berths in the past six seasons.

The Liberty made Connecticut shoot 3-pointers, since it entered last in the WNBA in makes per game (5.7) and had attempted the third-fewest per game (19.0).

But the Sun still connected on them, and their 38-32 halftime lead was anchored by six made 3s on 15 attempts.

The Liberty couldn’t generate a response on offense until the third quarter, when Stewart, Vandersloot and Ionescu (17 points) took over as Jonquel Jones sat against her former team with foul trouble.

Beyond any strategy, any movement and spacing improvements that Stewart and Vandersloot addressed afterward, that dominant stretch was how games were supposed to unfold.

It made everything — at least across 40 minutes early in the season — seem normal.

Stewart became the first player in WNBA history with at least 20 points, five assists, five steals and four blocks in a single game, according to ESPN.

She also set two franchise records, with the most points in a two-game span (66, surpassing Cappie Pondexter’s 64) and the most points in the first three games of a season (73, surpassing Tina Charles’ 71).

After the victory, Vandersloot glanced at Stewart’s numbers from the press conference table.

They weren’t as flashy as her 45-point game last week against Indiana, but Vandersloot said jokingly, “I’m just admiring this stat line that she has here, plus a black eye.”

“Don’t look at my free throws,” Stewart said from two chairs down, pointing out her 4-for-7 mark, which even surprised Brondello.

“She’s not perfect,” Vandersloot said. “Pretty close.”