NEW YORK — Jared Sullinger took a glance at the game clock and thought something must be wrong. With fewer than six minutes left in the first quarter, he was still in the game.

There was a good reason he hadn’t been subbed out yet, though.

In an experimental 44-minute preseason game, Sullinger had 21 points and 19 rebounds to help the Boston Celtics beat the Brooklyn Nets 95-90 on Sunday.

“I’m so used to seeing 12 (minutes) and I looked up and I saw 5-something on the clock. I’m like, man, normally I come out at the 7-minute mark,” Sullinger said. “They said, ‘No, it’s an 11-minute (quarter).’ So that explains everything.”

Jeff Green added 14 points for Boston (4-3), hardly deterred by playing 4 minutes fewer than a normal NBA game.

Backup point guard Jarrett Jack and reserve center Jerome Jordan each had 17 points for the Nets (2-1).

The idea of a shortened game arose during the NBA coaches’ offseason meeting as a way to analyze and compare the flow of the game with that of the league-standard 48 minutes.

“You noticed it a little bit when you’re subbing at the start of quarters, but I thought the flow with the one less timeout was actually a little bit better in the second and fourth,” Celtics coach Brad Stevens said. “I didn’t notice it other than that.”

While an average game takes 2 hours, 15 minutes, the game Saturday took 1 hour, 58 minutes. Instead of the customary 12-minute quarters, Sunday’s game featured four 11-minute periods along with a reduction of mandatory timeouts from three to two during the second and fourth quarters.

The opening quarter was played in 19 minutes, the second in 29 minutes, and the third and fourth in 25 minutes each.

“I’m looking at the clock and it’s 7 or 6 (minutes remaining) on the clock and I have to get myself back because only 5 minutes have gone off if it says 6 on the clock,” Stevens said. “That’s a little bit different, but I had it mapped out so I kind of knew what I was going to do.”

Brooklyn power forward Kevin Garnett sat out against his former team because of a stomach virus.

Playing their first game since returning from a trip to China, the Nets shot 5-of-19 from the floor in the third period.

“The third quarter seemed like we ran out of gas and the China trip really caught up with us,” coach Lionel Hollins said. “The energy started dropping. We started taking bad shots and turning the ball over.”

Brooklyn point guard Deron Williams, who played 25 minutes but was rested for the entire fourth quarter, couldn’t really pinpoint the effect the shortened game had after it was completed in under 2 hours.

“It’s really hard to tell a minute a quarter (and) 4 minutes a game. When you’re out there in real time, you’re not really thinking about it,” said Williams, who played just more than nine minutes in the second quarter and a little less than nine in the third.

BULLS

Guard Butler sprains left thumb: In Chicago, Bulls guard Jimmy Butler sprained his left thumb in the Bulls’ exhibition game against the Charlotte Hornets on Sunday night.

With about 5 minutes left in the first quarter, Butler deflected a pass from Charlotte’s Michael Kidd-Gilchrist. Butler immediately grabbed for his hand and remained in the game for most of the rest of the quarter, but was ruled out before halftime. He scored two points in 11 minutes.

Butler averaged a career-high 13.1 points last season.

KINGS

Sacramento picks up McLemore’s option: The Sacramento Kings have picked up the 2015-16 option on guard Ben McLemore’s contract.

General manager Pete D’Alessandro announced the move Sunday. McLemore averaged 8.8 points and 2.9 rebounds in 26.7 minutes last season as a rookie.

McLemore was picked seventh overall by Sacramento in the 2013 draft.

The Kings also waived center Sim Bhullar, guard Deonte Burton and forward David Wear to reduce their roster to 15 players.