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MILWAUKEE -- The last time Jayson Tatum suited up for a game at Fiserv Forum, the Boston Celtics were down 3-2 to the Milwaukee Bucks in the second round of the playoffs last season. Tatum responded with the best, and most important performance of his career -- a 46-point, nine-rebound masterpiece in Game 6 to keep the Celtics' season alive. 

His 40-point, eight-rebound effort in Thursday night's 140-99 win for the Celtics wasn't nearly as important, but his shot-making was just as impressive. He went 12-of-18 from the field, including 8-of-10 from 3-point land and 8-of-8 from the free throw line, to equal his most efficient shooting performance of the season and record his 11th 40-point game of the season. 

Tatum got plenty of help from Jaylen Brown, who finished with 30 points, five rebounds and five assists as well as major contributions from Al Horford and Malcolm Brogdon, each of whom chipped in 14 points. As a team, the Celtics shot 22-of-43 from behind the arc to tie the fifth-most 3s they've hit in a game this season. 

"I just thought we were very detailed," Celtics coach Joe Mazzulla said. "We were detailed in our scouting, we were detailed in our personnel. We were detailed in how we were gonna attack offensively, and we made shots. But outside of the making shots I thought we had a different approach to our mindset tonight, and it's something we have to continue forward."

Here are some key takeaways from the Celtics' impressive win:

Celtics keep hope for No. 1 seed alive

The Celtics were in control of the top spot in the Eastern Conference for much of the season, but that all changed in February when they stumbled and the Bucks ripped off a 16-game winning streak to jump them for both the best record in the league and the No. 1 seed in the East. 

Entering Thursday's matchup, the Celtics trailed the Bucks by three games and were looking at a must-win to keep any slim chance of reclaiming the No. 1 seed alive. With their emphatic victory, the Celtics narrowed the gap to two games, but more importantly, they secured the tiebreaker between the two clubs. Now, if they finish with identical records at the end of the season, the Celtics would get the top spot.

Of course, that's a big if. The Celtics have five games remaining: at home against the Jazz, a quick road trip to play the Sixers, then back home for a two-game set with the Raptors and one versus the Hawks. As for the Bucks, they'll be home against the Sixers, away to the Wizards, back home to play the Bulls and Grizzlies, then on the road versus the Raptors. 

The Bucks' magic number to clinch the No. 1 seed is four, which means they'll need a combination of four wins and/or Celtics losses. After this result, though, they'll have the Celtics hot on their tails. 

"[The No. 1 seed] does matter," Brown said. "So we want to finish out the season strong and see what happens."

Tatum's 3-point shot returns

Tatum won the All-Star Game MVP Award in February by hitting 10 3-pointers en route to his record-setting 55 points. Unfortunately for him and the Celtics, he seemed to have used up all of his 3-point shooting ability that weekend, when he also participated in the 3-Point Contest. 

Coming into Thursday's showdown with the Bucks, Tatum was 42-of-143 (29.4%) from 3-point land since the All-Star break and had not made more than six 3s in a game. That all changed in this one. He missed his first attempt, then got it stuck on automatic and finished 8-of-10 from deep in his best 3-point outing of the season, let alone since the break. 

The even better news for him and the Celtics is that he hit a number of tough pull-up 3s. Tatum is an elite player at all times, but he reaches another level when he has his off-the-dribble jumper dailed in from distance. We saw that last season in Game 6, and we saw it again on Thursday night. 

Nothing illustrates the importance of Tatum's shooting more than the fact that for the season, the Celtics are 16-1 when Tatum hits at least five 3s. Even if you lower the threshold, they're 22-5 when he makes at least four of them. 

So what was the difference on Thursday? "They went in," Tatum said. 

"I just think he trusted his shot," Mazzulla added. "I want him to trust his shot, I want him to shoot the open ones and I thought he did a good job of that."

Both sides weigh in on possible playoff preview

Regardless of how the seeding shakes out at the end of the season, the Bucks and Celtics are clearly the two best teams in the East and will finish 1-2 in some order. That would set up a potential Eastern Conference finals showdown, which would not only be a rematch of last season's seven-game series, but the fourth time in six seasons they've met in the playoffs. 

The Celtics have the upper hand in the rivalry. They won the first-round series in 2018 and the second-round series in 2022, while the Bucks took the second-round series in 2019. In addition, the Celtics are now 2-1 against the Bucks this season; both wins came by at least 20 points, and the only loss was in overtime with most of the starting lineup out injured. 

What, if anything, does all of that mean for a possible playoff preview?

"We got a lot of history with them, very familiar with them," Tatum said. "Tonight we shot the ball well, they didn't shoot it well. If we play them again in the postseason, it's probably not gonna be like this. They feel like they probably could have played a lot better, and they missed a lot of open shots, so there's some things that we gotta clean up. Probably down the line we'll see them again, and it's gonna be a tough battle."

While Tatum and Co. tried to downplay the significance, the Bucks' main man thought this game was a significant reminder to his team. 

"We know what the deal is, it's not hard to understand," Giannis Antetokounmpo said. "If you're not focused, if you don't play hard, they're gonna kick our ass. Simple as that. They did it tonight, won by 40. If you're not locked in, if you don't play hard, if you don't go out there to make it tough for them, they're gonna kick our ass. 

"There's no level of concern, it's a fact. You have this in your head, and it's up to us to see how we're gonna deal with it. Are we gonna go and play the same way, and if we play the same way, we're gonna have the same outcome. We gotta change some stuff, we gotta compete, we gotta have some pride. If we do that, maybe we have a chance to win."