Boston • The Jazz fought back to be in a position to win, so most of them were relatively upbeat following a 98-93 loss to the Celtics.

“It’s not that frustrating when you know that you had opportunities to win the game,” forward Paul Millsap said. “It wasn’t anything they were doing, it was something we had control over.”

The Jazz (4-5) had five shots in the final minute to either take the lead or tie the game, but missed them all. While Millsap remained upbeat, Al Jefferson said he would walk out of TD Garden with his head held high and coach Tyrone Corbin was “proud of the way our guys fought,” the harshness of the loss sank in for Mo Williams in the corner of the visitors’ locker room.

The Jazz point guard dressed slowly, and softly discussed the final plays of the game with Marvin Williams: Why he short-armed the 3-pointer with seven seconds left, why he didn’t dribble back out before missing a layup with 21 seconds left.

Not that frustrating?

Don’t bother trying to sell that idea to Mo Williams, who took the loss — in what could have been the Jazz’s signature win — as a personal insult.

“I just wish I could have closed it out for us,” he said. “But, I’ll take and make that shot — or miss it — time and time again, if I’m in the position. I’ll shoot it with confidence. I have a lot of confidence in my ability.”

Late Wednesday, Williams took accountability for the loss on Twitter, saying he made a “couple bad decisions.”

Millsap had his second strong outing, following up his 34-point night Monday in Toronto with a team-high 20 points and 12 rebounds. Four other Jazz players reached double figures, including Mo Williams, who finished with 14. However, the point guard spent the rest of the night wondering why he couldn’t make one more basket.

Williams had the ball with 32 seconds left, but rather than play for a 2-for-1 situation, held on to the ball. The result was the missed layup he replayed in his mind, over and over.

“Playing back the first shot with my head,” he said. “I don’t know. I think … I don’t know. It felt like I was moving too fast for some reason. The play we drew up kind of broke down.”

The Jazz sustained several runs by the Celtics, who got help from all corners. Paul Pierce led all scorers with 23 points, but both Leandro Barbosa and Jeff Green added 16 points off the bench for Boston.