WALTHAM - Since the arrival of Ray Allen and Kevin Garnett in 2007, the Celtics have lost more than two straight games at home only twice. But unless they can solve their defensive and rebounding problems against Chicago tonight, they will have a three-game home losing streak.
A failure to get defensive stops down the stretch was costly in a 90-85 loss to Dallas Wednesday. But coach Doc Rivers was optimistic after analyzing the team’s play yesterday.
“We’re getting closer, actually,’’ Rivers said. “I was more encouraged than discouraged. The rebounding problem, we have to fix.
“But a lot of the other things - defensively we were really good until we gambled. We lost 12 big points on gambles and 9 were down the stretch, which you can’t do. And that’s what I meant about discipline.
“Overall, I like some of the things we’re doing. We have to get better defensively and start games better.’’
Rivers also saw positive signs from the bench, which was sparked by Mikael Pietrus, making his Celtic debut.
“Without the second unit, we’re losing that game by 25 points,’’ Rivers said. “Second unit got us back in the game with their energy, then the first unit came back and started making some shots.
“That’s what I envisioned when we started this. And that was the first night you could literally see a difference - probably because Pietrus was part of it.’’
Defensive chance-taking left the Celtics out of position on key plays.
“The first two games, it’s been terrific since then,’’ Rivers said of the defense. “I don’t like our defense down the stretch. We’ll have a great defensive possession and someone, just one guy, will gamble or become undisciplined. And it can be any of them. And it breaks down the whole set.
“They are not doing it because they are selfish, they are doing it because they want to win. And that hurts you more than it helps you.’’
Jason Terry converted an open 3-pointer to give Dallas an 82-79 lead with 3:18 remaining.
“[Rajon] Rondo gambled on that,’’ Rivers said. “He went for the steal and you can’t do that. The play was going to be stopped. Brandon [Bass] was set for the charge. Dirk [Nowitzki] had nowhere to go; he could only go to Terry and that wouldn’t have been there if Rondo would have stayed.
“There were like five of those down the stretch. That’s where discipline has to get back to where we want it.’’
Asked about the Celtics’ status as an elite team, Rivers said, “We’ll have to find that out. I think we are. We’re 4-5 and our record says we’re not. And we say we are. I warn you, we’re only nine games into the season.
“What I’m saying is, it’s early, guys. And coaches are always worried. Concerned, worried, that’s what I should be; 10-0, and I’m concerned we’re overconfident.
“We really haven’t beaten anybody yet, and we have to do that, eventually, if we’re going to be an elite team.’’
The Celtics fell behind Dallas, 10-2, shooting 0 for 7 to start the game.
“It’s always the starters,’’ Rivers said. “They just have to do a better job. If you saw our first eight shots, I think we would like those same eight shots every night. They were not just open shots, they were wide open. We missed three layups. What you going to do, tell them to make them?’’
Neither Keyon Dooling (knee) nor Jermaine O’Neal (knee/hamstring) practiced yesterday. Dooling is questionable for tonight, but O’Neal will likely play. The Celtics are hoping to develop Avery Bradley or E’Twaun Moore as a backup for Rondo. “We would like Keyon at the 2 more, and that’s where we’re trying for Avery or E’Twaun to take that 1 spot,’’ Rivers said. “Keyon is better at the 2 spot than the 1.’’
Going for a ride
Pietrus scored 5 points and committed four fouls in an 18-minute stint in place of Paul Pierce against Dallas. “I just said Pietrus had it going and I’m going to ride that,’’ Rivers said. “Paul obviously wants to play and he also saw that, too. No big deal. It’s a tough one because you knew at some point Pietrus was going to get tired and if you sit Paul too long - that’s the danger about riding guys. He was our best practice player [for] two days and then again today. But I still didn’t think he could take it over to the game. The game is completely different, and he did.’’ Pietrus dunked off a steal late in the third quarter. “He’s been great, wonderful,’’ Rivers said of Pietrus’s defending. “We switched him onto a 4 and that’s when he got the steal, and that was the right read.’’