The 76ers were looking to come back from their 109-101 loss to the Boston Celtics in Game 1 of their Eastern Conference opening-round series. Both teams had different starting lineups in Game 2 on Wednesday. Here are some observations from the 128-101 loss.

Where’s the ‘D’? The only reason the Sixers led by as many as 14 points in the first quarter was that Boston missed several open shots. The open shots were still there after the first quarter, and once the Celtics got hot they made the Sixers pay. The Sixers offered very little defensive resistance after the first quarter, and the Celtics continually buried them.

Big early development: Jayson Tatum got two fouls in the first three minutes of the game. Both fouls were not against his man but while helping on defense. He stayed in a few minutes before leaving the game. But on a Celtics team that lacks depth, that didn’t help having him leave the game before it was five minutes old and the Celtics down, 13-8. When he returned with 3 minutes, 36 seconds left in the first quarter, the Celtics were down, 27-14. What was key was Tatum didn’t pick up another foul before halftime, when the Celtics led 65-57 with Tatum scoring 18.

Coaching challenge: Knowing he needs Joel Embiid on the floor as much as possible, Sixers coach Brett Brown challenged a foul by his center in the first quarter against Marcus Smart. The call was reversed, and Smart was assessed an offensive foul for bumping into Embiid.

Another quick start from Embiid: For the second straight game, Embiid came out on fire. In Monday’s loss, he had 11 first-quarter points and hit all five field goal attempts.

On Wednesday, he had 15 first-quarter points and hit 6-of-9, including four jumpers of 12, 16, 17 and 19 feet.

Then came the second quarter: Embiid didn’t post up very much in the second quarter, and the Sixers offense stalled. The Sixers’ ball movement was great in the first quarter, not so much after that. Even though Embiid had a big scoring night, he didn’t come close to matching his first-quarter output.

How do you stop this? Tatum, with the shot clock running out late in the first quarter, drilled this three.

Matisse Thybulle contested the shot (and might have fouled him), and Tatum still made it.

Tatum had it rolling: The Sixers started Thybulle to guard Tatum. While Thybulle had success in Game 1, holding Tatum to 2-for-9 shooting in matchup minutes, according to NBA.com, it wasn’t the same in Game 2. Tatum scored against any defenders the Sixers had, and for the second game he was a dominant force.

Defending the high pick and roll: The Celtics had great success by shooting threes off the high pick and roll.

On the above video, Philadelphia product Brad Wanamake gets a pick from Enes Kanter and makes the three. Especially in the second quarter, Boston feasted on this play.

Richardson aggressive: After scoring 18 points in Game 1, Sixers guard Josh Richardson has remained aggressive. Richardson was playing as if he felt nobody on the Celtics could stop him off the dribble, and he was able to get to the basket freely. Richardson kept the Sixers in the game with 14 first half points.

Defensive play of the game: Marcus Smart is among the best defensive players in the game, and he showed it on this blocked shot.

Despite a five-inch disadvantage, Smart came over from the weakside and rejected the shot of Tobias Harris.

Boston mixes in zone: The Celtics on a few possessions in the third quarter threw a zone defense on the Sixers, and it was effective.

Sixers also show zone: The Sixers also went to a zone at times in the third quarter, and it appeared to momentarily take the Celtics out of their rhythm. But Romeo Langford and Tatum hit consecutive threes, and Tatum added a driving layup late in the third quarter, and the zone didn’t look so good.

Solid Celtics subs: With Gordon Hayward out due to a Grade III right ankle sprain, it was a major blow to the Celtics, a team that isn’t supposed to have much depth. Yet Wanamaker and Enes Kanter and rookie Grant Williams had productive performances.