For Rivers to say he implemented even a facsimile of the defense (or any other defense for that matter) that Thibodeau implemented is laughable. Rivers is a nice guy, but his ego supercedes the obvious. The disgraceful defensive exhibition of the three seasons previous to this one and every other season Rivers has coached speaks to that.
It helps to have Garnett to anchor anybody's defense. But without Thibodeau, Boston's defense with Garnett would more resemble Minnesota's defense the three seasons previous to this one. Decent, but far from outstanding.
This is on Thibodeau implementing, and probably led by Garnett, the players buying into a completely different mentality. Rivers gets credit for keeping the egos (other than his own) in check. But defensively, Rivers was just along for the ride.
Vs the Triangle? Again, it helps to have an athletic 7ft freak anchoring, and an energized Paul Pierce playing defense like he did under Jim O'Brien. Paul, the last 3 seasons, defended like Tank Carter. This season, he defended like Bruce Bowen.