Darien gutted out a challenge from host Greenwich, winning 3-0 by tight scores on Friday.
The Wave (10-0) edged the Cardinals (8-1) 26-24 in the first game, 25-21 in the second and won 25-17 in the third.
Kelly Kosnik cracked 13 kills, and Riley Sousa 12 to the floor.
Celia Martzolf and Kosnik scored 12 service points apiece, while Brittany Osborn had 10, Sousa six, Lauren Pryor five, Taylor Cockerill three.
Osborn led with six blocks, Cockerill had four.
Martzolf made 33 assists.
Kosnik led Darien with 17 digs, Sousa got down on 12, Pryor 10, Osborn seven, Martzolf five, Keli Reyes four, Cockerill one.
Kosnik received 20 serves, Sousa met 15, Pryor and Osborn greeted nine each.