The Sixers started the regular season with a 107-93 win over the Boston Celtics.

Here are David Murphy’s four takeaways from the season opener on Wednesday:

The defense showed up

This defense is everything it was billed to be. The one vulnerability that the unit was supposed to have did not look like a vulnerability at all. After laying an egg in their regular season finale, as the Wizards’ small lineups gave them all sorts of trouble, there was plenty of reason to wonder how the Sixers’ oversized starting five would look against a Celtics team that would have the ability to force Al Horford to match up against either Jaylen Brown or Gordon Hayward at the four. At no point did it appear to be an issue. In fact, the Sixers defense was even more formidable than anybody could have hoped, with the Celtics clearly frustrated with their inability to generate any clean looks. There was a possession with about five minutes left in the third quarter when Horford ended up isolated on Jayson Tatum on the right wing. As Tatum explored him with his dribble, the third-year standout clearly did not feel comfortable pulling up due to Horford’s length. But he was unable to create any separation off the dribble and ended up leaving his feet without anywhere to go with the ball, resulting in an errant pass that the Sixers easily stole. That was pretty much the story of the night, the Sixers’ length giving them more than enough margin for error to compensate for whatever speed/agility deficit they faced. The Celtics finished the night shooting just 36.4 percent from the field, including 6-for-25 from three-point range.

Ben Simmons was aggressive

Ben Simmons doesn’t need to shoot three-pointers if he gets to the rim the way he did in the Sixers’ half-court offense. Lost in all the hoopla about his jump shot is the fact that he is still has a ton of room to grow his ability to get to the rim and finish. Against the Celtics, he did both with abandon, playing with as much control of his body as we saw at any point during his first two years with the team. Late in the second quarter of a game that the Sixers had been trailing throughout, Simmons seemed to take the game on his shoulders, driving hard to the hole on at least five possessions during the closing minutes of the first half. Just before halftime, he exploded to his left after catching a pass from Tobias Harris with his defender out of position and threw down a ferocious one-handed dunk that pulled the Sixers to within one point. Throughout the night, he was both aggressive and in control, connecting on eight of his first nine shots and entering the fourth quarter with 18 points, five rebounds, and five assists (and four personal fouls, at least two of them on the offensive end, a further testament to his aggression). With about eight minutes remaining, he coasted to the rim in transition and almost flippantly banked home an easy right-hander over a helpless Daniel Theis. The next time down the court, he took a pass from a double-teamed Harris and finished with his left hand. Simmons finished the night with 24 points, nine assists and eight rebounds on 11-of-16 shooting, in addition to playing rock solid defense.

Point guard defense wasn’t a major issue

The previous four times the Sixers had faced Kemba Walker, the diminutive point guard had scored 21, 60, 30 and 37 points against them. In a lot of ways, Walker personified the Sixers’ struggles against small, quick-scoring point guards in recent seasons. On Wednesday night, however, Walker epitomized how much different this Sixers defense is going to be this season. Led by Josh Richardson and Matisse Thybulle, the Sixers frustrated Walker throughout the night, holding him to just 12 points on 4-of-18 shooting from the field. Richardson was every bit the player that Brett Brown built him up to be during the postseason, a high-energy pest on the defensive end of the court who plays with noticeable zest for the game. There were several times when he reacted to a big defensive stop by clapping his hands and clenching his fists and nodding his head, including a full-court press that caught the Celtics by surprise and resulted in an eight second violation in the third quarter. With 10 minutes left and the Celtics in the midst of climbing their way back from a double-digit deficit, Richardson poked the ball away from Jayson Tatum in transition to thwart a Celtics odd-man rush, one of 16 Celtics turnovers on the night. But it was his work as Walker’s primary defender where he shone the brightest.

It was a similar story for Thybulle. The Sixers wasted little time throwing him into the fire, subbing the first-round pick into the game with 7:13 left in the first quarter and immediately tasking him with guarding Walker. And Thybulle more than held his own. While there were certainly some rookie moments, he played an important role in the Sixers ability to frustrate one of the league’s premiere scorers off the dribble. The highlight was probably a loud block of a Walker layup attempt late in the third quarter. But from a holistic standpoint, Walker’s inability to get any easy looks was probably the greatest testament to Thybulle’s play. Early in his first shift against Walker, Thybulle picked up a foul on a dribble handoff, then, on the same possession, successfully turned another DHO attempt into a deflection into the back court. Thybulle picked up his third foul with 5:39 left in the second quarter while attempting to block a Walker pullup from behind. Still, considering his role, his NBA debut was a resounding success.

Tobias Harris finds his groove

After one quarter, you might have wondered whether Tobias Harris was on his way to setting the single-season record for fewest touches by a max contract player. But as the game wore on, the newly-minted mega millionaire found his way, culminating in a three-pointer from the left wing with nine minutes remaining that gave the Sixers an 83-73 lead and knocked out whatever remained of the Sixers’ wind. No doubt, this offense is a work in progress. It was not a pretty game by any stretch of the imagination. Joel Embiid was surprisingly quiet in the half court offense, although perhaps it is not that surprising when you consider that the Celtics double-teamed him nearly every time he touched the ball. The big man finished with 15 points on 5-of-14 shooting, including 1-for-4 from three-point range. Still, the frequent double-teaming opened things up elsewhere. The Sixers missed a number of wide open three-point looks that would have turned this game into a blowout had they not finished 7-for-29 from three-point range.