Clearly, Boston's stoppers won the first skirmish.
In Boston's 92-88 win over the Magic in Sunday's Game 1, Orlando had its worst offensive performance of the postseason by far. You may think the simple fact that the Celtics have a great defense explains that. But Orlando's offense, to date, has been able to overcome great defense to score efficiently. The Magic aced Charlotte's excellent defense in the first round, and the Hawks usually get plenty of stops. Just not against the Magic.
The Celtics, meanwhile, saw their defensive performance continue, despite facing another great offense after vanquishing Cleveland in six.
There are a lot of ways to look at how well a given unit performs. My preferred method is to adjust for the opposing unit's quality. Holding the Magic to 88 points in 92 possessions is not the same as holding the Nets to that. In the graphic below, I've taken a look at Boston's defense performed in each playoff game relative to the opposing team's regular season offensive efficiency. For example, the Heat averaged 106.6 points per 100 possessions in the regular season. In Game 1 of Miami-Boston, the Heat were held to 85.7 points per 100 possessions. Therefore, the Celtics defense held the Heat to an offensive efficiency 20.9 points lower than normal. The same is done with Orlando's offense and its opposing defenses. This helps add some context to the margins each team has been tossing up through the postseason.
Boston's defense held Miami's offense to an efficiency almost nine points per 100 possessions lower than normal in the first round, and saw Cleveland's offensive efficiency dip 7.5 points per 100 possessions. Orlando's offense scored 9.5 points more per 100 possessions than Charlotte had normally given up, and a whopping 20 points more than Atlanta had typically allowed.
But in Game 1, Orlando was slowed. The Magic's offense has its first "loss" of the postseason, with the Boston defense performing 8 points per 100 possession better than usual. The Magic's offense was 16 points per 100 possessions worse than usual, a Boston defensive effort comparable to the Celtics' best nights against Cleveland and Miami.
This ignores the Orlando's own excellent defense did a good job against Boston's hot-and-cold offense. But the Magic have excelled in this postseason on offensive acumen. It looks, at least temporarily, as if Boston has an answer Charlotte nor Atlanta could summon. The Cavs dredged up just one incredible offensive performance against the Celtics. The Magic have to hope their own comes in Game 2.