Defensive breakdowns cost the Celtics in overtime loss to Knicks

A lot has changed since Ime Udoka replaced Brad Stevens as head coach, with new faces lining the bench as both players and coaches. We've also seen a new offensive approach, one which tasks the players with increased movement both on and off the ball.

However, the most notable change has come on the defensive end. Udoka has employed a stringent "switch everything" system. However, miss a rotation or react a second too slow, and everything unravels pretty quickly.

Overall, the Celtics did a good job sticking to their defensive principles during the first half of the game. When switched onto bigger players around the post, guards were doing a fantastic job at getting low into their man's body while denying passing lanes, and wings were switching in tandem around the perimeter. There were still some mishaps, but you're guarding an NBA-level offense; there's no way you can shut down every possession.

In the second half, cracks began to surface. Switching isn't a new philosophy in the NBA, and as such, coaches and players know how to counter this brand of defense. A slip here, a dribble hand-off there and throw in some off-ball screens for good measure. Once the Knicks diversified their offense to include these counters, the Celtics began to struggle in their decision making. For reference, we've seen these counters work against the Celtics throughout the preseason, and while some of the kinks have been ironed out, there are still some creases that need addressing.

For instance, the Celtics opted to give their best Evanescence impression by going under on almost every dribble hand-off during the second half and overtime, allowing the Knicks to generate shooting pockets for their scorers. Evan Fournier was a big beneficiary.

"Defensively, we need to tighten some things up. Just get better at communicating. It was loud in there. Those New York fans are always loud. But we could have communicated a little better, and we let Fournier get going towards the end, and that just can't happen,” Jaylen Brown explained after the former Celtics wing went for 23 points during the second half and overtime.

Going under on hand-offs was certainly not part of the plan, but it also wasn't the compounding issue for the defense that came in transition. "If you're not involved in the play on the weak side, or if you're not crashing, even if you're a big, you got to start making your way back. We work on transition drills every day, and we have got to tighten up some. I think it hurt us at times in the preseason. We just got to keep working on that, knowing that if you're not in the play or not crashing, you're getting back and building that wall," Udoka said after the Celtics gave up 14 fast break points - twelve of which come after halftime.

All-Star Julius Randle was a clear thorn in the Celtics side, and he demanded large amounts of focus from the Celtics defense, with Grant Williams, Marcus Smart, and Rob Williams all taking their turn to guard him. After Randle cooked Grant Williams a few times (not entirely Grant's fault), Udoka changed the defensive structure, something the head coach thinks played a part in the Celtics' missed coverages at times.

"We switched from switching everything to switching 1-through-4, and guys got a little confused and went under a little bit expecting Rob to switch out. Changing our coverages in the fourth quarter and overtime, we wanted to keep Rob on Julius Randle. And some of our guys just messed up the coverage, we got to be more communicative, we switched it up late in the game, and I know we made a few mistakes that kept them in the first overtime for sure."

Perhaps the change in system did lead to some blown coverages and to players opting to go under on screens, but relying on Williams to switch onto a shooter and affect a jump-shot on every pick-and-roll play is a risky strategy anyway. But, the Celtics ran similar pick-and-roll coverages during the preseason, where the big would switch onto the perimeter, and the guard would operate in a "veer back" role.

The "veer back" role is where a guard will switch onto the roll man in pick-and-roll sets and look to get in front of them before sinking into their body (usually below their waist) to slow the roll down and kill any lob or post-entry threat.

Udoka mentioned how the team’s emphasis was on stopping Randle and that they felt good about their "smalls" dealing with the threat of Robinson. "We got Al missing right now, so that's part of it. We just really wanted to force their hand. We knew we could play up-tempo and hurt them, like we did in the first half and most of the second half. We liked the match-up with Rob (Williams) on Randle, so we felt comfortable with all our smalls on Mitchell Robinson to keep the big matchup with Rob there. So we kind of staggered him and Grant (Williams)."

Obviously, you don't want your guard being posted up by a sturdy big such as Robinson, but using a guard's speed and agility to veer back on defense is a solid plan to limit a roller's presence in the paint.

Learning a new defensive system that entails multiple switches per possession (both on and off-ball) is going to take time, especially when Udoka will be switching between "everyone switch" and "X positions switch." For all of the Celtics' struggles on the defensive end in the second half and overtime, some highly encouraging moments displayed the team's potential in this system.

Unfortunately, the Knicks and coach Tom Thibodeau were brilliant in their adjustments and put the Celtics into deep waters with how they wanted to defend. It was painful to watch at times, but as a learning experience, the Celtics will be better for it, and hopefully fix some of their mistakes before Friday’s game against the Toronto Raptors.