How did the New York Rens improve enough to match the Original Celtics?

The New York Rens improved to reach parity with the Original Celtics by refining their passing game and team defense.1

Initially, the rivalry was lopsided in favor of the Celtics, who were led by stars such as Joe Lapchick and Nat Holman. However, as the Rens continued to face the Celtics in high-stakes "race games," they developed their tactical execution to the point where they became the only professional team capable of claiming equality with them. This commitment to high-level team play eventually earned the Rens recognition as the finest exponents of team basketball, a sentiment echoed by legendary coach John Wooden, who noted that he had never seen a team play better team basketball.1