In the first quarter of an early-season matchup between the Bucks and Raptors, All-Star guard Kyle Lowry came off a pick-and-roll with OG Anunoby and found space on the left wing. With Bucks forward Ersan Ilyasova dropping back toward the paint, Lowry could have launched a pull-up 3-pointer, a shot he has used regularly to punish flat-footed defenders.

Instead, Bucks guard George Hill recovered and utilized his long wingspan to challenge the attempt, leading Lowry to second-guess his choice and turn the ball over. The Bucks flew out in transition, and Hill scored an easy two.

This kind of play is not an unusual sight at a Milwaukee game. The Bucks possess three of the best rim protectors in the league in Giannis Antetokounmpo, Brook Lopez and Robin Lopez. Coach Mike Budenholzer drops his bigs back and dares opposing ballhandlers to drive into a sea of arms. That's part of the reason why the Bucks are posting a defensive rating of 101.0, the stingiest mark in the league.

The less heralded part is what the guards are doing at the point of attack. They have perfected the art of the rearview contest.

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For those unfamiliar with the terminology, it's a simple (but not easy) defensive strategy. On a standard pick-and-roll set, defenders will often choose to switch assignments and live with a mismatch. The Bucks largely prefer to keep thei

r centers closer to the basket and have the guard chase over the screen to avoid that scenario.

Bucks guards aren't just capable of recovering. They are quick and athletic enough to block or alter jump shots.

Hill, Eric Bledsoe, Pat Connaughton, Donte DiVincenzo — it's a long list of backcourt stoppers. Milwaukee preaches the importance of on-ball defense and teaches the proper way to execute rearview contests. It also doesn't hurt that the Bucks have exceptional athletes.

"It's certainly something that we work on, and we talk to them," Budenholzer explained after Milwaukee beat Charlotte on Sunday. "But I think all those guys are really gifted defensively. They're athletic. They can get shots. You get one, earlier in the season you block a couple shots, they see it. What Bled does from behind, Donte, George, Pat, it's something they're really good with.

"They just take some of the stuff we give them and they run with it and make it better."

Staying attached to the ballhandler is of utmost importance. The Bucks know how to slither and slide around screens, and if the screener doesn't connect with a physical guard like Bledsoe ...

"It's very rare, but it's something that we emphasize," Hill told Sporting News. "We know right now we should have the Defensive Player of the Year in Brook back there blocking shots. We have another (NBA All-Defensive) First Team big man in Giannis on the defensive end, so our job is just to do the best we can without getting screened, contest shots.

"Normally guards are scared to go in and go draw layups versus our bigs because Brook does so well protecting the rim and things like that. We know that they normally shoot a lot of pull-ups, and it's just trying to get late contests."

Those contests can also come away from the ball. Connaughton is a specialist in running down his man like a ridiculously intense game of tag and then leaping from behind to get a piece of the shot.

Combine hyperactive guards with an intimidating backline, and boom, there's the No. 1 defense in the NBA. The Bucks lead the league in the following categories: defensive rebounds per game, defensive rebounding percentage, opponent field goal percentage and opponent points in the paint.

And despite the level of aggression, Milwaukee is a top-five team in terms of opponent free throw attempt rate.

"I think we all just try to do a good job contesting. Getting vertical, not necessarily making contact ... just try to change or alter it any way we can," Brook Lopez said. "Coach obviously preaches being careful about fouling, limiting fouling. I don't know if it's something you really want to think about in the moment — you obviously want to get the best contest — but at the same time, I think guys like Robin and Giannis and our bigs are very skilled at getting that great contest without fouling.

"Honestly, even the guards in their rearview contests, Bled, Donte, George in their rearview contests when they challenge threes, they do a pretty good job as well of contesting without fouling."

It wouldn't be a surprise to see Antetokounmpo or Lopez win the 2019-20 Defensive Player of the Year award. They are both deserving candidates for their work as defensive anchors.

Just remember there are a few guys in front of them making sure the system doesn't fall apart.