Joel Embiid explains how each player on the floor needs to be "on" every night in order for the Sixers to be "unbeatable." (1:05)

The NBA says Aron Baynes should have been whistled for a foul on Joel Embiid with 14.6 seconds left in Wednesday night's closeout Eastern Conference semifinal game between the Boston Celtics and Philadelphia 76ers.

Boston led 111-109, and after the game, Embiid -- who would have gone to the line if the call had been made -- said he felt he was fouled.

The league agreed in its "Last Two Minute Report" published Thursday.

The Celtics went on to win 114-112 to take the series 4-1 and advance to play the Cleveland Cavaliers in the East finals.

"I mean the play unfolded, and I mean the refs, they had a great game, I thought they were great tonight," Embiid said. "But I mean I felt like there was something on that last play, but you can't really do anything about it. But they did a great job the whole night."

The league also said Marcus Smart traveled when he caught Ben Simmons' full-court heave with 1.5 seconds left in the game. That would have given the Sixers the ball back with a chance at a go-ahead 3 or tying 2.

The Sixers left TD Garden with a stinging disappointment after losing their second-round series.

But there was an underlying optimism about what might lie ahead for Philadelphia. After winning only 23 percent of their games in the previous four seasons in an attempt to build through the NBA draft, the Sixers finished the regular season with 52 victories and won a playoff series for the first time since 2012.

But the Celtics surprised the Sixers -- and the rest of the NBA -- by winning the series in five games. Boston outplayed Philadelphia in clutch time throughout the series, outscoring the Sixers 51-39 when games entered the final five minutes with a margin of five or fewer points.

"The Process is never going to end," Embiid said. "This is a process to get to the playoffs, we did it. This was a process to get to the conference finals, we didn't. Next year, that's our goal."

Information from ESPN's Ian Begley and The Associated Press was used in this report.