BOSTON – The Celtics remained undefeated in the preseason with a 139-89 victory over the 76ers at TD Garden on Saturday night. Boston led by as many as 54 points against an undermanned Sixers squad that rested all of their eight best players when they played back-to-back against the Timberwolves on Friday night.

Boston’s starters enjoyed an early celebration against the 76ers’ deep reserve, building a 40-18 lead in the first quarter and blossoming from there. Jaylen Brown (18 points) led six different Celtics in double figures, while Jayson Tatum added a double-double with 16 points and 10 rebounds in just 23 minutes before taking most of the second half off. Rookie Jared McCain had a game-high 20 points in the setback for Philadelphia.

Boston improves to 3-0 in the preseason with the win with two games remaining, starting on Sunday night against the Raptors. The Sixers fell to 1-2 with the loss.

Here are four takeaways from the Celtics’ win on Saturday night:

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Cornet shines while Horford rests: The Celtics are content to spare Al Horford some wear and tear this preseason as he missed his third straight game. Luke Kornet continues to start at his spot and had one of the best halves of his career against the 76ers’ reserves. He led all scorers in the first half with 15 points and helped the hosts collect 12 second-chance points thanks to five offensive rebounds. Kornet will be a player that opposing defenses won’t focus on all season, especially if he’s on the floor with the starters. However, his size and hoops IQ allow him to find easy looks inside the offense and on the glass, as evidenced by his 7-for-10 shooting from the field. Boston’s frontcourt depth will be tested early in the year with Kristaps Porzingis sidelined, but Kornet is continually looking up to the task for bigger minutes.

Starters already seem ready for regular season: After a five-day break, Joe Mazzulla rotated his starters (minus Al Horford) to their usual workload in the first three quarters and the results were promising. Boston’s stars were involved on both ends of the court, while the team’s cohesion remained as good as ever. The level of competition wasn’t exactly a challenge for this group, but Mazzulla has to be pleased with the sense of purpose this group brings to winning a title. With only two preseason games remaining in the next three days, it wouldn’t be a surprise to see this group pull off a quick first-half cameo in Toronto on Tuesday night. You don’t have to risk anything now that this group is working so well.

Guerschon Yabusele looks like he belongs: The former Celtics big man started at center for the Sixers, with the team resting the majority of their regular players. Yabusele couldn’t prevent the Sixers’ bench from being run off the floor by Boston’s starters, but the 28-year-old held his own during his twenty minutes of action. He knocked down a pair of threes and posted a total of seven points and three rebounds, along with a block. In addition to stretching the floor from the rim, Yabusele also bullied Jayson Tatum on a post-up for an easy layup. The Sixers don’t have many high-energy options off the bench in their deep rotation, so it appears Yabusele has a chance to fill that role.

Lonnie Walker shows the best version of herself: The veteran guard was demoted to pick up duties in his first two preseason games with Boston. On Saturday night, Mazzulla gave Walker a chance with Boston’s regular bench rotation and he made the most of it. Walker (nine points) is known for his aggressiveness with his shot, but he was a pass-first player against the Sixers, tallying seven assists off the bench, including several unselfish runs. He was also annoying on defense (two steals, one block) and seemed like a worthy wild-card option on Boston’s second unit for at least one night. It will still be an uphill climb for him to make the final roster, but it is now easy to see the team’s vision to bring him on board for a closer look after this outing.