One surprise tweak Brad Stevens made with Jayson Tatum is already paying off

Most NBA playoff series are all about matchups. Knowing where you can attack or hide your weakest defensive link is a critical component to getting the best of any team in a seven-game series.

The Celtics and Pacers played Game 1 on Sunday but they had plenty of time to feel each other out since it’s looked like these two squads have been destined for each other since late March.

"They did some things a little differently then they had in the last two games in a lot of ways," Brad Stevens said after Game 1. "This not like Game 1. This was almost like Game 3 because we had played each other a couple of times in the recent weeks."

Boston made its move towards a Horford/Baynes starting frontline with the knowledge this series was coming down the pike. It’s a decision that paid dividends down the stretch of the regular season as the C’s closed out the year with a 6-2 record, including two head-to-head wins over the Pacers to lock up home court in the first round.

The Celtics learned a few things about themselves in those late-season matchups, but they also had to do plenty of tinkering with their gameplan in the last week once Marcus Smart went down with a torn oblique. His defense is never going to be replaced by anyone on the roster individually but his ability to match up with all of the Pacers guards and wings from Darren Collison to Bojan Bogdanovic created some intriguing choices for the coaching staff without him.

A lot of the focus heading into Game 1 was on who exactly would get the call to replace Smart in the starting five and as we predicted here at BSJ, Jaylen Brown got the nod. Despite a subpar offensive game, Brown did his job admirably on Bogdanovic, limiting him to just 12 points on 4-of-11 shooting in conjunction with Gordon Hayward and Jayson Tatum. Hayward’s ballhandling and playmaking was a necessity for the bench unit so Brown sliding into the starting five in a defensive-minded role was a natural fit.

The bigger defensive strategic tweak in Game 1 though didn’t come on the personnel front, though. Instead, Stevens and his coaching staff made a surprise move in regards to matching up with the Pacers' starting five and it involved relying on the 21-year-old Tatum in a way we have not seen much this season, while baiting the Pacers into a more preferable matchup.

A big part of the Pacers' gameplan this season against the Celtics was putting a target on the back of Kyrie Irving. Nate McMillan had his guys run Irving through multiple pick-and-rolls in the 104-102 loss to the C’s at the Garden last month, a strategy that produced plenty of open looks and mismatches. Sometimes, point guard Darren Collison would get all the way to the hoop or he would get a switch, which would open the door for a bigger player to post up against Irving.

Smart has often helped out Irving on this front by taking tough ballhandlers whenever possible in order to keep Irving from having to stop offenses at the point of attack. Smart's presence undoubtedly helped Irving put together the best offensive numbers of his career because he didn’t have to chase around point guards all of the time Smart was on the floor with the starters, preserving more of his energy for offense.

With Smart out of the picture, though, and Brown assigned to chasing Bogdanovic on the perimeter, Stevens made an intriguing adjustment in Game 1 that the Pacers likely didn’t anticipate: He had Tatum guard Collison almost as much as Irving, slotting the All-Star on Matthews instead.

Tatum spent 12 possessions or 25 percent of the time he was on the floor guarding the Pacers' point guard, limiting him to 1-of-3 shot attempts. That was double the amount of time he played on him during the March matchup with Indy (Collison missed the April 5th matchup due to injury).

So what exactly does this move accomplish for Boston? A few key goals were accomplished when the Celtics limited the Pacers to a season-low 74 points in Game 1.

1. Taking some pressure off Irving/saving his energy: Collison is one of the quickest guards in the league and he snakes around pick-and-rolls quite well when fully engaged. With the ball in his hands so often with the Pacers starting five, Irving really has no place to hide and/or rest on the defensive end of the floor. Tatum taking over this assignment for a good chunk of his minutes allows Irving to get away from the ball and avoid running into Pacers big men screen time and time again. Tatum isn’t great at this, but he’s stronger and longer than Irving, which helps in this instance. Meanwhile, Irving gets to recharge a bit more and preserve more of his energy for offense.

2. Keeping Collison out of the paint: There probably isn’t anyone on the Celtics roster that gets stuck on screens more than Irving. Some of it is due to his size, other times its effort, but it’s a trait that leaves the Celtics in a bind and creates open driving lanes. By using Tatum in place of Irving on Collison, the Celtics were able to make life a little tougher for the 6-foot point guard. Tatum has an eight-inch size advantage on him which makes it both tough to pass around and shoot over. Collison didn’t try to do much of either in Game 1 against Tatum as his 1-of-3 line indicates since McMillan fell right into the C’s trap on a lot of possessions.

3. Baiting the Pacers into Matthews post-ups: Wesley Matthews used to be an elite offensive player and a deadly weapon on post-ups against smaller guards, but that was before he tore his Achilles three years ago. Now? He’s a strong 3-point shooter making just 38 percent from the field while trying to prove he’s worthy of a big deal on the free agent market this summer at age 32.

Matthews facing Irving in the post does tilt towards the Pacers but it’s not nearly as big of an advantage as they might think. Irving, when engaged, fights hard down low and any time the Pacers go to him over some more efficient offensive options (Bogdanovic, Turner, Young), that’s a net win for the Celtics defense. On a team full of weak offensive options for Indiana, Matthews is arguably the weakest among them, at least in the starters. Irving held up well on the post with plays like this:



This gameplan is not possible though if Tatum isn’t capable of holding his own against a player much smaller and faster than he is in Collison. The second-year forward has struggled with closeouts and defensive awareness at times during the regular season but he’s shown for sustained stretches in the past two years that he can be part of an elite defensive lineup. In fact, he did his best work last year with the starting five alongside Baynes and Horford and his defensive rating since the C’s went back to that big starting group is the best on the C’s roster (97.6).

If Tatum can stay strong in his minutes on Collison and continue to hold his own while defending the likes of Doug McDermott on the perimeter (1-of-5 while guarding him in Game 1), the Celtics may have found the defensive formula to win this series fairly quickly, even without Smart. When Tatum is on the floor, this team has consistently played well for the past two years and finding matchups like this for him only makes this team more dangerous. The Celtics are going to need his offense to get through the Eastern Conference gauntlet this postseason but what he’s capable of giving Brad Stevens on defense is just as important.