Stevens’ Smart-on-Lowry adjustment propels Celtics to Game 5 win

In a battle between two of the NBA’s best and most innovative coaches, it was a Brad Stevens adjustment that turned the tide on Monday as the Celtics claimed critical Game 5 to take a 3-2 series lead against the Toronto Raptors. Throughout the series and, truthfully, his NBA career as a whole, Nick Nurse has not been shy about trying out a variety of defensive schemes – we’ve seen the 2-3, 2-1-2, box-and-1, and many others just in this series from him in attempts to slow the Celtics down – but this time it was Stevens’ turn.

In Games 3 and 4, Kyle Lowry had been exceptional at putting his head down and getting inside the paint. In Game 3, he attacked the Celtics on the interior, notching 20 points in the paint with an additional three free throws. In the next game, Lowry continued to get inside, drawing eight free throws, and also managed to leverage the defensive attention he was getting when he penetrated, into opportunities for his other teammates, by kicking the ball out when the defense collapsed on him. He was constantly finding a way past Jayson Tatum and his matchups, and so in Game 5, Brad Stevens decided that he was going to stick his defensive stopper, Marcus Smart, on Lowry.

He switched Smart and Tatum’s defensive assignments, leaving Jayson to guard OG Anunoby. And, while the primary purpose of the switch may have been to prevent Lowry from having as much of an influence on this game as he did in the previous two, it also allowed Tatum to move back to more of an off-ball role, where he’s caused havoc all year, disrupting passing and driving lanes.

Photo by Mike Ehrmann/Getty Images

Before the game, Brad Stevens challenged the starting lineup to be better on the defensive end, and his adjustment was a big reason why the Celtics were able to hold Toronto to a franchise-record low 11 points in the first quarter. Prior to Game 5, the Raptors had actually won the 46 starter-only minutes 100-79, but Boston’s stout defensive start set the tone for the rest of the game, and I would be surprised if Smart didn’t stay on Lowry for the rest of the series.

The adjustment moved both Smart and Tatum into more familiar defensive roles that they had been playing all season, with Smart at the point of attack, and Tatum more in the passing lanes and helping on rotations. BBall-Index’s versatility app clustered players based on the amount of time they spent guarding different kinds of players, with UG1 being high-usage 25+ MPG guys, and the following groups being less “important” offensive players, all the way down to UG6, who are those playing <15 MPG. This graphic shows how much time each player spent guarding the top-3 usage groups, with Smart most regularly taking the tougher assignments and Tatum classified as an off-ball wing, spending more time on UG3 players than on UG1 or UG2.

Per NBA Stats’ matchup data, after spending just 10:26 on Lowry in the first 4 games combined (compared to 20:34 for Tatum which lead the team), Marcus Smart was Lowry’s primary assignment for 5:26 in Game 5 (44% of the time Lowry was on offense). While he doesn’t have the length of Tatum, Smart has the strength and defensive chops to stick with Lowry even as he puts his head down on those drives. By preventing Lowry’s constant penetrations into the middle of the paint, he closed off a big avenue of Toronto’s offensive success. After averaging 26.5 points and 7.5 dimes in the two wins, Lowry was held to just 10 and 5 in the fifth game.

Tatum was also able to make a much bigger impact on the defensive end being placed on OG Anunoby instead of Lowry. While he is by no means even a below average on-ball defender, Tatum’s real strength defensively comes in his ability to read the game and make the right rotations and clog passing lanes with his long arms. While Anunoby’s been shooting the ball pretty well all series, he’s much less of a threat off the dribble and has the ball much less than Lowry, freeing Tatum to do more of that free safety work.

With Gasol charging down the lane here, Tatum plays this perfectly, rotating at just the right time to prevent the pass to the corner, and does enough to deter Gasol at the rim – eventually leading to an easy Theis flush on the other end. If he’s there too early, Gasol can find OG in the corner, and if he’s late, it’s an easy dunk, but Tatum gets there at just the right time to make the play.

A lot of Boston’s defensive success this season has come thanks to their three-headed perimeter monster in Smart, Brown, and Tatum. Part of that is thanks to the balance of Brown who thrives on-ball, Tatum who’s better off-ball, and Smart who can do both. Stevens found a way to get all three back in their ideal defensive roles in Game 5, but the Celtics still constantly switch, and so it’ll be interesting to see if Nick Nurse tries to set some screens to get Smart away from the point of attack in Game 6.