BOSTON -- Celtics coach Doc Rivers admitted the decision made little sense. Switching to a zone defense against one of the league's elite shooting teams invites danger, particularly for a Boston squad that prides itself so vehemently on its man-to-man approach.
But Rivers wondered out loud to his coaching staff at the team's morning shootaround how often the Warriors had even seen a zone defense this season. He figured it might be a good changeup to throw at them on Friday night.
So with ace defender Avery Bradley sidelined by foul trouble for much of the second half, Rivers elected to go with the unconventional zone approach. The Warriors responded by shooting 30.2 percent and mustering a mere 40 points on 53 shots after the intermission as the Celtics emerged with a 94-86 triumph at TD Garden.
"We almost had to [go zone], because we had Courtney [Lee] in foul trouble -- and Avery," said Rivers. "This morning, my thought was, 'How many times are they ever zoned?' I just thought that, they shoot the ball so well, I don't think they've been zoned that much and I think [assistant coach] Kevin [Eastman] looked it up; it was 70 minutes this year. So we just went with it and it worked. I mean, they missed some shots in it, but I thought the switching and the zone was really good for us."
According to Synergy Sports tracking, the Warriors have seen zone a mere 79 possessions this season, 1.5 percent of their total 6,031 possessions. Golden State averages 0.94 points per play overall -- 10th-best in the league -- but that number jumps up a bit to 0.962 points per play against zone, and the Warriors have scorched opponents by shooting 50 percent against it.
Bradley has professed a dislike for zone in the past; Kevin Garnett gets uncomfortable just talking about it. But with Bradley on the bench with five fouls just four minutes into the second half and Golden State surging ahead, Rivers made the switch.
And it worked.
"The zone was big for us," said Courtney Lee. "I think we kept a stat that they were 0 for the first eight possession of the zone. It was huge for us. Avery picked up his fifth foul early and then I was in foul trouble a little bit, so everybody stepped up and did their role."
A little 9-0 burst late in the third quarter tore apart a previously tied game and helped Boston keep Golden State at arm's length the rest of the way.
"That's something that we've been working on," said Bradley. "Not only that, I think our communication -- we got a lot better as a team in the zone, and it showed tonight. We played great zone defense."
But you're not supposed to be able to disrupt a quality shooting team with a zone.
"That's why we did a great job talking," said Bradley. "We were switching; everybody was pointing and talking. That's why we were able to run the shooters off their shots tonight."
Bradley and Lee will take great pride in having helped limit Golden State's Stephen Curry to 25 points on 6-of-22 shooting. Combined with Klay Thompson (15 points on 7-of-19 shooting), the Warriors' starting backcourt shot a mere 31.7 percent.
Boston mixed the finesse of the zone with some early physicality aimed at making the Warriors work for their points. Bradley hounded Curry early and often and, by the time Bradley retreated to the bench late in the first quarter, Curry had more turnovers (2) than points (1).
Curry got himself going at times, but Boston refused to let him take over the game. When Bradley and Lee were on the bench, there was an emphasis on communication to aid Jason Terry and Jordan Crawford when they were tasked with keeping Curry from having a New York-like outburst (he dropped 54 points against the Knicks at MSG on Wednesday).
"[The zone] was a different look. Good shooting teams, you've got to be very, very talkative in the zone," said Garnett. "I was kind of leery of it, but it was a different look. I thought it was a great call on Doc's part. He and [assistant coach] Mike [Longabardi] made a great call and I thought it slowed them down and I thought they went to a more individual game. I thought that played into our favor. More importantly, we got stops when we had to get stops. We rebounded together and just came out with a win."
According to Synergy Sports data, the Celtics rank sixth in the NBA in allowing a mere 0.898 points per play (a number that's dropped steadily since Bradley returned to the lineup). Boston actually owns the fourth-best man-to-man defense, allowing 0.846 points per play in half-court sets. But the Celtics are not afraid to throw the zone changeup and with good reason: Despite the fact that zone has accounted for a mere 145 possessions (2.7 percent of total plays), the Celtics have allowed only 0.786 points per play and opponents have shot 35.6 percent against it.
Teams eventually sniff out the zone and make changes to bust it. Golden State got lulled into firing away, and when shots didn't fall, Boston capitalized.
"I think it really bothered them," said Pierce. "They're a great one-on-one team that really thrives on taking you off the dribble, making an extra pass, shooting the 3-ball. ... I think it altered their offense a little bit once we got into the zone."
Playing zone might make Boston uncomfortable at times, but it made Golden State far more uneasy on Friday night.