Four Rounds: Biggest NBA Finals questions for the Celtics and Mavericks

It's Celtics vs Mavericks in the NBA Finals, baby! Luka Doncic or Jayson Tatum will win their first championship. Kyrie Irving or Kristaps Porzingis will exact revenge against their former team. It all starts with Game 1 next Thursday. Let's use this week's Four Rounds column to preview the matchup with the four questions that will define the series before ending with my series prediction.

1. What happens when the Mavericks are on defense?

The Mavericks will mostly play this straight up, with PJ Washington on Jaylen Brown, Derrick Jones Jr. on Jayson Tatum, Kyrie Irving on Derrick White and Luka Doncic on Jrue Holiday. Dereck Lively II (or Daniel Gafford, if Lively isn’t available) will be slotted onto Kristaps Porzingis (or Al Horford, if Porzingis isn’t available).

The Celtics beat the Mavericks in both regular-season meetings, but just one of them took place after Dallas remade its roster at the trade deadline, on March 1. Josh Green was still starting at the time and the Mavericks lost by 28 points. In that game, they were reluctant to switch any of Boston’s small-big actions so that they had a 7-footer on Porzingis, but they were more willing to let a small (and Doncic) switch onto Horford. 

I’m curious if the Mavs will swap the Irving and Doncic assignments. By putting the 6-foot-7 Doncic on White, they can more freely switch the White-Tatum actions that Boston likes to get to. On the other hand, Doncic can more freely play off Holiday and be positioned as a roving low-man the way he was in their series against the Timberwolves.

The Celtics will try to punish Doncic and Irving, pulling them into pick-and-rolls and using staggered screens to get them switched onto mismatches. 

The Mavericks are a much better defensive team than they were in their March meeting. Jones, who played just seven minutes in the last game, gives them a legitimate wing defender with size to defend Tatum and Brown. They are also more connected – their closeouts, rotations and execution are all better. This is — by far — the best defense the Celtics have faced in the playoffs.

Can Dallas limit the amount of good 3-point looks the Celtics get? The Celtics are averaging nearly 40 3-point attempts per game in the playoffs, making them at a 37 percent clip. But they also didn’t see much interference. 

2. What happens when the Celtics are on defense?

While the Mavericks went with straight-up matchups, the Celtics junked it up. They had Brown on Doncic, White and Green, Holiday on Irving, Porzingis on Washington and… here’s the wrinkle… Tatum on Lively.

Why? So that they could easily switch the Doncic-Lively pick-and-rolls. This way, Doncic was always facing one of Boston’s like-sized defenders, Brown or Tatum.

The Mavericks countered by running their pick-and-roll offense with Washington, pulling Porzingis into the actions.

It worked a bit, but it definitely defanged the Mavs’ halfcourt offense. It takes Washington away from his bread-and-butter as a corner 3-point shooter and Lively away from reaking havoc as a roller. 

In their March meeting, the Mavericks accepted the matchup and didn’t push to get Lively more involved in their halfcourt offense (Lively scored 15 points in the game but most of that came from him running the floor in transition). 

Eventually, instead of planting Lively in the corner, the Mavericks experimented some with putting Lively in the dunker spot, where he can feast on lobs and offensive rebounds. I expect more of this in the Finals.

The Mavericks’ defense will have to help fuel their offense. By running off misses, they don’t give the Celtics a chance to cross-match and then they can get to their regular stuff.

The Celtics also have their work cut out for them when defending 77, who had 37 points on 56 percent shooting in January. If Luka can’t get an opposing center switched onto him, he’s fine targeting Boston’s guards. White and Holiday are awesome defenders against most opponents. Luka wasn’t bothered by them. Too big. Too strong. Too crafty. 

3. Who is the biggest X factor?

We can get cute with the Washingtons and Whites of the world, but it’s Tatum. If he doesn’t get outplayed by Doncic, then the Celtics probably win this series.

Let’s go back to the 2022 Finals. The Celtics had a 2-1 lead when Steph Curry erupted for 43 points on 54 percent shooting in Golden State’s Game 4 win to tie the series. Tatum in that game finished with 23 points on 35 percent shooting and turned the ball over six times. He then scored just 13 points and had five turnovers in the championship-deciding Game 6, when Curry masterfully scored 34.

One of the ways Tatum has grown since that series is in taking care of the ball. He averaged 4.2 turnovers per game in the 2022 playoffs. He’s down to 2.4 in these playoffs. The Mavs don’t force a ton of turnovers, but they are opportunistic.

Doncic and Irving are going to make tough shots. That’s just what they do. Brown has been a needed source of one-man offense in Boston’s egalitarian system this postseason and earned the Eastern Conference finals MVP award. 

If Tatum doesn’t rise to the occasion for these Celtics, all the trades, five-out offense and net ratings will have been for nothing. 

4. How do the paths for each team impact the Finals?

The Celtics will have had nine full days off by the time Game 1 of the Finals tips off on June 6. The Mavericks will have had six days off. Both are long breaks compared to most seasons and should allow for plenty of rest.

What I’m more concerned about is the level of competition these teams have faced to this point. This isn’t meant to disparage Boston’s path as “easy,” but there’s something to be said of not being tested. The Celtics pretty much play the same way now as they did at the end of the regular season. They haven’t been forced to grow, solve puzzles or find solutions. 

Part of that is because they were already far ahead of most teams in the league this season. They established a system, they mastered it quickly, and then they rolled to the league’s best record. 

But the Mavericks have seen some stuff, man, and have had to pull different levers and push different buttons to get to this point. Against the Thunder, they were the bigger team and relied on their frontcourt size and on-a-string defense to win a seven-game series. Against the Timberwolves, they had to switch gears. Suddenly, they were the smaller team, and they had to take down a team that had just knocked off the defending champs. The Mavericks' 111.5 defensive rating in the playoffs is only a smidge behind Boston’s 110.6 defensive rating in the regular season.

Doncic and Irving have leveled up defensively, playing the best defense of their careers. Lively, a rookie, has logged more playoff experience than some players get in an entire career. Guys like Washington and Gafford have gone from playoff mysteries or proven performers.

These teams are more evenly matched than what the regular-season records and early prognostications suggest. We’re in for a helluva series.

Prediction: Mavericks in six.