Even Celtics  coach Doc Rivers  couldn’t watch a full preseason game against a Nets team that didn’t send any of its starting five out for the opening tip. Conveniently, the second half of the C’s 97-96 loss coincided with the start of the presidential debate, and that’s when Rivers — an ardent support of President Barack Obama, a fellow former Chicagoan — excused himself, “allowing his assistant coaches to handle the bench duties.”
At least Paul Pierce  stayed for the second half, capping a 29-point night on 10-of-17 shooting (6-8 3P) in 27 efficient minutes. Jeff Green  (14 points) and Courtney Lee  (13 points) also stuck around until the end of the C’s bench eventually coughed up a double-digit lead in the final minutes. Here’s what else Rivers missed.
WHAT WENT RIGHT
Sharp Pierce: After entering training camp out of shape and suffering a foot injury that lingered long past the three games he missed to start the 2011-12 NBA season, Pierce seems prepared to begin this season in much better shape, showing no ill effects of the knee injury that hobbled during the playoffs. The Celtics captain connected on four of his first seven shots against the Nets , scoring 10 of the C’s 14 points in the opening seven minutes.
Green party: After struggling for the first time all preseason against the 76ers, Green turned in another aggressive performance, recapturing his leadership role on the second unit. After falling hard to the floor early in the second quarter, he shook off the trainer and even drew a charge on the other end. If there were any lingering questions about Green’s hesitance after returning from heart surgery, he answered them in that stretch.
On guard: Lee’s outside shot wasn’t dropping (1-4 3P), but the C’s starting shooting guard once again demonstrated the athleticism and defensive ability that made him so coveted. Also, his chemistry with backcourt mate Rajon Rondo  is clearly developing, as Lee found open spots on the perimeter and Rondo naturally found him with a few nice crosscourt passes. Eventually, the career 39 percent 3-point shooter’s stroke will connect.
WHAT WENT WRONG
Opening statement: The Celtics shot just 35 percent in the first quarter against a Nets team that started Keith Bogans, C.J. Watson, Josh Childress , Reggie Evans  and Andray Blatche . Outside of Pierce (4-8 FG) and Rondo (2-3 FG), the rest of the C’s combined to make 1-of-9 attempts. That’s not good. Not good at all.
Smallie bigs: While Nets center Brook Lopez  got the night off, Rivers started Jared Sullinger and brought Brandon Bass  off the bench for the third time in five games, lending more credibility to his seriousness about starting the rookie at times alongside Kevin Garnett  in the frontcourt during the regular season. However, without Darko Milicic  (thumb), Rivers tested both Bass and Sullinger at the 5 in stretches, and neither made a statement much louder than Jason Collins  for backup center minutes. Just ask Blatche (23 points, 9 rebounds).
Terry time: We’re still waiting for that first real Jason Terry  explosion off the bench. In 68 minutes over three games against NBA competition, Terry has scored a total of 18 points. He scored 18 or more points in 21 games for the Mavericks during the regular season last year. While he received a standing ovation from a halfway filled Garden crowd — and deservedly so — Celtics fans have yet to see the JET truly take off in green.