WASHINGTON -- If Celtics coach Doc Rivers had trouble knowing exactly what he'd get from his team before Saturday's game, Boston's 89-86 win over the Washington Wizards didn't do much to establish expectations.

After tinkering with the lineup by inserting rookie Jared Sullinger as the starting power forward, the Celtics responded with an energized, defensively efficient 17-2 lead in the opening minutes.

Later came the offensive drought and poor rotations that allowed Boston to blow all of its lead and trail late in the fourth quarter.

But then the Celtics got back to what they know best. Actually, it was more about who they know best: Paul Pierce and Kevin Garnett.

"I made a point of it," Rivers said. "I reminded our guys that Paul was on our team and Kevin was on our team. I loved that at halftime, they had the most shots. That's how it's got to be every night."

Identity crisis solved.

At least for a night.

Pierce scored 15 of his game-high 27 points in the second half, including eight in the fourth quarter, to provide the clutch offense. Garnett forced a turnover on Washington's potential go-ahead possession with 28 seconds left and Boston avoided a second straight 0-3 start to the season.

Beating a Wizards team that was missing its two best players in John Wall and Nene wasn't exactly viewed as a breakthrough accomplishment for the Celtics.

But for a Boston team long on recently acquired veterans and short on chemistry, it was a modestly productive step forward for a team that remains a work in progress.

"I don't think we're close," said guard Rajon Rondo. "But our heads and our hearts are in the right direction. We've got to continue to buy into the system, what coach is telling us to do every night and we'll get there. We've got the right approach to the game each night, and it starts with defense."

Rivers saw some familiar signs.

For example, Rondo pieced together another double-double, with 12 points and 12 assists. It extended his double-digit-assists streak to 27 games, which ties John Stockton for the third-longest streak in NBA history. The Celtics shot only 42.9 percent from the field, but their 36 field goals came on 24 assists.

The Celtics' reputable defense also held the Wizards to 21 percent shooting in the first quarter, and to just 35 percent in the fourth.

Boston's bench produced a double-figure scorer for the third straight game, with Jeff Green contributing 11 of the 27 points scored by the reserves.

So there were encouraging signs. The next step is consistency.

"We got our first win under our belt, but now it's just time to build on it," Pierce said. "We understand it's a building process. It's up to us. We got the lead up, then it came back down, then we went up again and it came back down. So that's the part we have to build on, to build consistency where we put teams away. Even though we won the game, it's definitely one we can learn from."

Rivers wouldn't commit to Saturday's lineup moving forward. One of the reasons he went with Sullinger was to get a passer and rebounder in the starting lineup alongside Garnett and Pierce. The move pushed Brandon Bass to the bench to add more inside scoring.

Rivers hinted there could be tweaks and changes until Avery Bradley returns from shoulder rehab in about another month.

At some point, the Celtics will hit their stride. For now, they're a team trying to regain some semblance of balance after stumbling from the gate.

"We've got to get a fire under this team and play with some edge," Garnett said. "We've got to make sure we understand who we are. At the same time, we're still building. Guys are trying to still understand who they are. In terms of identity, we're still a defensive team first."