The Celtics have raced to a 10-2 record through Friday, but Sunday’s home game brings a different kind of challenge: Cooper Flagg and a Mavericks team searching for its next big step. Dallas is 7-5, and its season has already swung from two huge wins to a rough loss at Minnesota on Thursday. That makes this 6 p.m. EST meeting a chance for the Mavericks to show how quickly they can answer back against one of the East’s hottest teams.

Boston has built its early success with balance. The Celtics score 114.3 points per game, yet their defense may be even more important. They have won their last three games, including a five-point battle with Toronto on Wednesday after decisive victories over Philadelphia and Milwaukee. That mix shows a team that can run away early or stay steady when every stop matters.

Jayson Tatum is the center of that story. The 6-foot-9 forward leads Boston with 26.3 points per game, but his 7.5 assists show that he is also creating shots for teammates. He can power toward the rim, rise for difficult outside shots, or spot an open cutter. Dallas will need several long, active defenders ready to take turns guarding him.

Paul George gives Boston another smooth wing scorer and a disruptive defender. He is listed day-to-day with an illness and expected to return Sunday, so his status will be important. If he plays, his outside shooting could stretch Dallas’s defense far from the basket. Derrick White adds calm playmaking in the backcourt, while Boston’s 38.1 percent three-point shooting forces opponents to protect every corner of the floor.

That is where Flagg enters the picture. The Dallas forward is not simply a scorer. His 24.6 points, 6.9 rebounds, and 6.5 assists per game reveal a player who can change the game in many ways. He can drive into traffic, chase rebounds, find teammates, and swipe the ball away on defense. Against Boston, Flagg’s biggest job may be helping Dallas avoid rushed passes. The Mavericks turn it over 16.5 times per game, nearly two more than the Celtics, and extra giveaways can fuel Boston’s fast breaks.

Kyrie Irving gives Dallas another creator who can twist through tight spaces and make tough shots. His 39 percent shooting from three-point range gives Flagg room to attack. Still, Dallas will miss center Dereck Lively II, who is out with a foot injury. Without his rim protection and above-the-rim finishing, Daniel Gafford and the Mavericks’ other big players must battle hard for rebounds against Boston’s physical frontcourt.

Dallas has the athleticism to make this exciting, and its 8.8 steals per game show it can create sudden momentum. But Boston owns a plus-11.2 average scoring margin, compared with Dallas’s plus-1, and has looked more complete in recent games. Expect Flagg to make plenty of plays, but the prediction is a Celtics win because Tatum’s all-around control, Boston’s sharper ball security, and the home crowd should carry the night.

Cooper Flagg Brings Dallas’ New Challenge to Boston