ORLANDO — With 35.2 seconds left and the Celtics trailing the Magic by 6 points Sunday, coach Brad Stevens called a timeout, ostensibly hoping for a quick steal or a quick foul.
Orlando’s Elfrid Payton then received a long inbounds pass in the right corner, and three seconds later he had taken a path of no resistance and dunked the ball with one hand. The normally reserved Stevens turned, threw his dry-erase board against the floor, and stomped toward the end of the bench, muttering as he walked.
That frustrating segment encapsulated a frustrating and ultimately fruitless evening for the Celtics, who coughed up a 20-point lead and fell to the Southeast Division’s last-place team, 103-98.
“I thought that they really had their way with us,” Stevens said of the Magic. “They ripped the ball out of our hands on a couple occasions. They made physical, tough plays over the last three quarters that we didn’t match.”
The Celtics had appeared reinvigorated recently. They had won five of their last seven games, with the only two losses coming against two of the NBA’s elite teams — the Warriors and the Cavaliers.
And so this lukewarm effort came at a surprising time. It came just as the Celtics appeared to be finding their way.
“They were the aggressors and we weren’t,” guard Isaiah Thomas said. “We played soft and timid. You can’t win games like that.”
It is too early for Boston to begin obsessing over playoff position because of one loss, but it is also true that if this team hopes to be relevant in April, it cannot afford to drop games to the Magic in March.
Brandon Bass had 19 points and 17 rebounds to lead the Celtics. Thomas added 21 points and nine assists, but he made 5 of 14 shots and was never able to seize control of this game in the way he has seized control of so many others recently. As a team, the Celtics shot 39.3 percent from the floor and were outrebounded, 56-48.
Victor Oladipo led the Magic with 22 points, 7 rebounds, and 5 assists, and Payton added 19 points and 10 rebounds. Orlando was without injured center Nikola Vucevic (ankle), who averages 19.7 points and 11.2 rebounds per game.
Stevens and the Celtics praised the Magic’s athleticism, and that athleticism was evident. But to this point, that athleticism had not stopped this team from accumulating a 20-43 record.
“These types of games we’ve got to have if we want to get to the playoffs,” Thomas said.
The Celtics have shown this year that few deficits are too big to overcome, but they have more consistently shown that no lead is safe. And that truth revealed itself once again Sunday.
With 10:57 left in the second quarter, a free throw by Jonas Jerebko gave Boston a 37-17 lead. From that point on, the Celtics were outscored, 86-61.
Stevens is unsure if the lapses are because of the team’s youth and inexperience, or if it is something more fixable. He is sure that the inconsistency cannot continue.
“Our margin is such that we’ve got to figure that out,” Stevens said. “We’ve got to be as good as we can in the things we can control. We can’t go off-page for a five-minute spurt, let alone 36.”
With the Celtics trailing, 66-61, in the third quarter, Stevens turned to an unexpected source for a spark.
Gigi Datome, the second player acquired from the Pistons in the Tayshaun Prince trade last month, had played in just two games with Boston and had scored a total of 18 points all season.
But in this game, he immediately drained a 3-pointer and scored 8 points over an eight-minute stretch, helping the Celtics regain an 80-77 lead.
“I’m trying to use my opportunity and do my best whenever it will come,” Datome said. “I felt good today.”
Boston led, 84-80, with 3:35 left, and then it began to unravel. Mo Harkless started the Magic’s 12-0 run by hitting a 3-pointer from the right arc, and Oladipo ended it with a driving layup.
In less than two minutes, a 4-point deficit had become a 92-84 Magic lead, and the Celtics had no answer.
With 28 seconds left, rookie guard Marcus Smart drove toward the basket and made contact with Payton’s face with his left elbow.
After review, the officials ruled that it was a flagrant-2 foul, and Smart was ejected.
Smart said he was simply making “a basketball play,” and said he asked the officials for an explanation.
“I went up to them, I didn’t scream at them, I said, ‘What was the call?’ ” Smart said. “And they said, ‘Flagrant 2. Bye.’ That was it.”
And that was it for the Celtics, too, as a game that started with such promise turned into an opportunity lost.
Adam Himmelsbach can be reached at firstname.lastname@example.org.