Good observation.
Several weeks back, I stated that the path to this squad's improvement was tightening the defense, especially the fundamentals (closing out, pressuring the ball in the high post, staying in front of ball-handlers, keeping hands up, etc.). As your post points out, the last two games have demonstrated what happens when players work hard to improve these fundamentals.
Battle has played well, but all five players have sharpened their attention to detail and kicked up their energy the last two games. For example, Lydon anchoring the zone allows his teammates to execute their responsibilities more effectively and to be more aggressive. In short, plugging players into their proper roles has helped maximize the team's potential (as it often does), though this team still has plenty of room to improve before the season concludes.
Offense may come and go. Defense should be constant. Fundamentals are forever.