If you were to design an offense in a lab specifically meant to attack drop coverage, you'd probably come up with something resembling the Phoenix Suns. The core goal of drop coverage is to take shots away at the rim by parking a big man in front of the basket, but those are shots the Suns don't particularly want anyway. The Suns took the fewest shots in the restricted area per game during the regular season. They'll take what they can get, but they are in no way reliant upon those looks.
But the jumpers that drop coverage tends to allow? Those are right up Phoenix's alley. The Bucks allowed the third-most 3-pointers per game in the NBA this season. Phoenix shot 37.8 percent on those shots, the seventh-best mark in the NBA. The Suns made 47.4 percent of their mid-range shots -- best in the NBA -- and attempted the fourth-most in the NBA at 16 per game. The Bucks allowed 15.9 per game, the second-most. On paper, this was always an extremely precarious matchup for Milwaukee.
The Bucks knew that. They went through a similar realization last round against Atlanta, when Trae Young scored 48 points in a Game 1 upset. He got there largely because of Milwaukee's commitment to that drop coverage. Just watch Young hit floater after floater over Brook Lopez to help lead the Hawks to victory.
Mike Budenholzer didn't want a repeat performance against an even more dangerous mid-range opponent, so he adjusted preemptively. The Bucks primarily switched ball screens in the early portion of Game 1. The benefit of switching is that it theoretically ensures that players are always guarded. The downside is that the player guarding the opponent is often a mismatch. As valuable as Lopez is in drop coverage, he's just as vulnerable as a switch defender. He's more mobile than he gets credit for, but in isolation against a superstar, he's just easy prey. So Chris Paul hunted him…
In truth, these aren't exactly great looks. Typically, when a guard gets a switch against a big man, he's looking to blow by him for an easy layup. These are all semi-contested jumpers, and given the size difference here, Lopez is capable of bothering Paul without being directly in his face. But this is Chris Paul we're talking about here, one of history's greatest mid-range shooters. He doesn't need much wiggle room to get a shot off. Drawing a matchup like Lopez, who can't play up on him without sacrificing layups, basically ensures that he'll have at least a little bit of room to fire away.
Devin Booker was another story. He's far more explosive than Paul at this stage of his career, and the Bucks acknowledged that. When he drew Lopez off of switches, Milwaukee panicked and sent extra help. Booker proceeded to kick the ball out for open 3-pointers.
By the third quarter, the Bucks conceded. With Phoenix leading by double-digits thanks in part to success against switches, the Bucks reverted to drop coverage, and it went about as well as you'd expect. Paul and Booker are used to having room to operate in the mid-range, and both took advantage by snaking their way through the paint for clean jumpers.
The Suns even found some success at the rim against drop coverage. On this play, for example, Lopez drops to protect against a layup, but P.J. Tucker doesn't switch onto Deandre Ayton. Instead, he chases Chris Paul into Lopez. That leaves only a tight window to pass, but again, this is Paul we're talking about. He sneaks it through the two defenders to give Ayton an easy lob dunk.
Eventually, the Bucks admitted defeat. With 4:42 remaining in the third quarter, Lopez left the game and did not return. He was hardly the only Buck to get punished on switches. Bobby Portis and Bryn Forbes were both victimized plenty, but Lopez was by far the most important, and that is the crux of the issue here.
The Bucks were not a deep team even when they were healthy. They intentionally stacked the top of their roster by trading so much for Jrue Holiday and hard-capping themselves in free agency, and without Donte DiVincenzo, there just aren't that many options for Milwaukee to adjust from a lineup perspective. If Lopez isn't effective, they essentially have one five-man combination that is somewhat reliable on both ends of the floor: their four starters playing with Pat Connaughton. The word "reliable" is doing a lot of work in that context. Connaughton is not Lopez. The talent drop is considerable. The Bucks are essentially being forced to choose between their best players and the ones best-suited to their matchup. Rock, meet hard place.
That is what makes the temporary solution Milwaukee found in the fourth quarter so unsustainable. Milwaukee won its only quarter of Game 1 by playing Giannis Antetokounmpo at center, and that is a lineup construction they will return to in this series, but it's not one they can rely upon all night. Milwaukee's thin roster essentially means that Lopez has to play a significant amount of minutes. It might not be 45, but it will almost certainly be at least 25, and that puts him on the floor more than enough for Paul and Booker to enter attack mode.
So what is the solution here, aside from more intentional stretches of Giannis at center? Well, there isn't an obvious one. Phoenix is well-suited to attacking virtually any pick-and-roll defense that doesn't involve the rare big man equally adept at all three levels. Lopez isn't one of them. Anything the Bucks do is going to be a compromise. Milwaukee found success in Game 2 of the Hawks series by maintaining the basic principles of their drop coverage, but not allowing Lopez to drop allow the way to the basket. Instead, he typically hovered around the extended free throw line and gave Young fits in the process.
Playing this way might allow Milwaukee's perimeter defenders the time they need to scamper back into the play, as Holiday so effectively did to create turnovers against the Hawks, but it comes with many of the same drawbacks as switching. Paul and Booker can shoot with very little space, so they'd likely pull into their jumpers right off of the screen.
The other option, and it's not going to be a popular one, would be sticking to their guns. Sometimes contested jumpers go in. Lopez wasn't great in Game 1, but it's not as though Paul and Booker were getting wide-open looks, either. Maybe the same defensive plan yields better results in Game 2 thanks to shooting variance. Alternatively, the Bucks could stick with the drop coverage they prefer and dare Paul and Booker to beat them on relatively inefficient shots. Denver tried that strategy. It didn't go well for the Nuggets, but shooting is somewhat random on a game-to-game basis. Perhaps with fewer fouls and even stingier rim defense, the Bucks could live with those shots.
There's no magic bullet here. There's no obvious adjustment that could fix Milwaukee's entire defense. Right now, the Bucks have a roster that isn't constructed to defend this specific opponent. Overcoming that defect is going to depend on a combination of stellar individual efforts, smart schematic tweaks by the coaching staff, and a degree of luck that the Bucks just didn't have in Game 1. They were vulnerable to a specific sort of offense, and the Suns rammed that offense right down their throats.