The Cleveland Cavaliers won the battle after taking down a Gordon Hayward-less Boston Celtics on the season-opener, but as this 2017-18 campaign has progressed, it’s the latter that’s winning the war.

The two Eastern Conference powerhouses started as mirror opposites, with the Cavs getting off to a 2-0 start, while the Celtics went winless through the first two games. The ship has turned around for both teams, though, as Cleveland has only managed to win three of their next 10 games, while Boston has gone on a league-best 10-game win streak — and it’s not a mere coincidence.

Since the start of the season on Oct. 17, the Cavs have logged the worst defensive efficiency in the league, allowing 113 points per 100 possessions, while the Celtics boast the best mark at 95.6 points per 100 possessions — 2.1 points better than second-place Oklahoma City Thunder.

Cavs have the NBA's worst defensive efficiency by 3.5 points. Celtics have the NBA's best defensive efficiency by 2.0 points. — Tim MacMahon (@espn_macmahon) November 10, 2017

The porous defense isn’t news for this Cavs team, as they have struggled through the latter part of the season with this same problem, and now even without a known defensive liability in Kyrie Irving and without the worst-ranked defensive point guard in Isaiah Thomas, they still face this same issue — which all points to coaching, instead of the actual personnel.

Irving has made a complete turnaround under coach Brad Stevens, who has had the 10-2 Celtics rank in the top five in rebounds and rebounding rate through the start of the season.