One, two, three, four, five 3-pointers made. It was a first quarter for the ages for lightning rod Nets guard Cam Thomas, and an opening period from hell for a Knicks team that secured a 124-122 victory over their cross-bridge rival but is still working to shore its defensive processes after a notable pair of franchise-altering offseason moves. The Knicks traded five first-round picks to the Nets for Mikal Bridges, then sent Julius Randle and Donte DiVincenzo to Minnesota for Karl-Anthony Towns. They have spent the early portion of the season building a defensive identity around Bridges as the team’s de facto point-of-attack defender. And in Brooklyn, the point of attack is Thomas, the former Kyrie Irving understudy who erupted for 43 points on 16-of-22 shooting from the field and 7-of-10 shooting from deep albeit in a losing effort against the Knicks on Friday. Thomas scored 19 points in the first quarter alone and made all five of his 3-point attempts in the opening period. His performance underscored perimeter defense as a necessary point of improvement for a Knicks team that wants to contend with the Boston Celtics for a shot at an NBA title this season. The struggles have dated back to the season-opener in Boston and have remained a constant through the Knicks’ early season: Jayson Tatum scored 37 in a 24-point Celtics victory Tyrese Haliburton got a ton of open looks in Game 2 but missed them all (0-for-8 shooting) in a 25-point Knicks win Darius Garland and Donovan Mitchell hung 59 combined points on close to 60 percent shooting in the third game of the season Tyler Herro scored 34 points and made eight 3s Haliburton put up 35 and 15 in the Pacers’ victory in Indiana And the back court combination of Zach LaVine and Coby White totaled 54 points in their buzzer-beating victory over the Knicks on Wednesday Add in the performance by Thomas — who frequently spliced the Knicks defense to finish at the rim or found open looks from beyond the arc — and there’s a clear trend of Tom Thibodeau’s crew struggling to guard perimeter scorers even though the roster was constructed in a manner that lended itself to accomplishing that very feat. Thibodeau touched on Bridges’ struggles ahead of tipoff against the star forward’s former team on Friday, characterizing them more as team defensive struggles than issues Bridges bears alone. “It’s hard because you’re doing things with five people. So oftentimes if someone get scored upon, maybe someone’s not in the gap, someone’s not reading the ball correctly. So there’s a lot of variables that go into it,” Thibodeau explained. “It’s not like baseball where there’s a hitter and a pitcher and you can say, ‘OK, that’s a strikeout. That’s a hit,’ and even that sometimes, it’s a line drive and it’s an out. But I think there are things that you can measure. There are some things we’re doing well defensively, but there are things we’ve got to get better at. “He’s guarding a lot of point guards and that sort of thing. When you’re evaluating pick-and-roll defense is the communication correct? Is the body position of the big correct? Is the shell correct? Are we closing the gap correctly? There’s a lot of things that go into it. We have to get better at a lot of things.” The Knicks were without Towns (left knee contusion) and Miles McBride (illness), while Jalen Brunson (sprained right ankle) and Cameron Payne (strained left hamstring) were listed as probable and played through their injuries. Brunson finished with a team-high 37 points and 7 assists on 12-of-20 shooting from the field — including the game-winning three in the fourth — and Bridges added 22 points on 4-of-7 shooting from downtown. OG Anunoby scored 25 points on 10-of-17 shooting from the field, and the Knicks moved back up to .500 with a 6-6 record. The Nets missed starting and backup centers Nic Claxton (back procedure) and Day’Ron Sharpe (hamstring strain), but Ben Simmons started at center and finished with 4 points, 5 assists and 7 rebounds in 25 minutes of action. The Knicks built a 21-point lead, but the Nets slowly chipped away in the final period and made a push when Anunoby fouled out with 4:15 left in the fourth and the Knicks up seven. The Nets took a 122-121 lead on a Dennis Schroder three with six seconds left in the regulation, but Brunson responded with a go-ahead three, and Bridges blocked a last-second effort by Schroder to send the game into overtime. The Knicks host the Nets one more time in another NBA Cup game on Sunday, then welcome the Washington Wizards in the second leg of a back-to-back before embarking on a five-game West Coast road trip. It’s clear they need to work on certain areas of their defense, but a win is a win, and the Knicks will take them as they come.