Even as they relish this chance to stare back at all the so-called doubters, the Celtics suddenly have a short-term – let’s call it luxurious – dilemma.

The biggest benefit of their four-game sweep of Brooklyn is time. From everyone’s assorted aches to giving Rob Williams the chance to shake off some obvious rust, it will be time well spent.

“It’s huge. Obviously more time for Rob,” said Jayson Tatum. “And then myself, everybody, this was a very taxing four games. It took everything on both ends of the floor. So getting these five or six days off are going to be very beneficial for everybody.”

It was the third lowest collective margin of victory (14 points) by the winning team in a playoff sweep in NBA history. But by playing for the second seed, and asking for the first-round matchup no one else wanted, the Celtics have actually made themselves stronger.

But don’t call them the best. Marcus Smart doesn’t want to reach that goal until the very end.

“I definitely have seen the other series and, for me, I think that we are not the best team,” said the Celtics point guard. “We still have some ways to go. We still have work. And, you know, we don’t really get too high on the highs nor too low on the lows.

“We have to have that mentality that we’re not the best team, because once you get that mentality that we’re the best team, you start to get complacent and things start to kick in and bad habits, and we don’t want that.”

The Celtics’ late-game execution against a fourth-quarter Nets comeback – Kevin Durant, unlike some others, played like he wanted to force a Game 5 in Boston – may have finally broken most of those well-publicized “bad habits.”

“One game at a time. That’s all, really, my mindset is focused on,” said Brown.

Their collective youth considered, the Celtics are also one of the most playoff-tested units in the field, with a tough four-game sweep of the Nets just another round of conditioning.

“At this point in time, we all know experience, depth and adjustments at this time of year,” said Smart. “That’s what it all comes down to – and obviously execution. So for us to be able to do what we’ve done, it’s part of it. Like I said, you tip your hat off to Ime and this coaching staff for getting us ready.”

ROBERT WILLIAMS returned nearly a week ahead of his planned recovery from knee surgery on his torn meniscus.

The Celtics center came off the bench in two games against Brooklyn, playing a total of 24 minutes over those two victories to help Boston close out the series. The work will ramp up much more for Williams in the next round – a likely matchup against the Milwaukee Bucks – but the big man is pleased with how his knee has responded thus far.

“No pain at all,” Williams said after Wednesday’s practice. “Knee is responding well. On recovery days, it’s responding well after days that are hard loads, so it’s good.”

The 4-0 series sweep will give Williams five full days to ramp up his fitness even more ahead of a potential Game 1 on Sunday.

“Just getting in the weight room a little bit more,” Williams said of his plans for the time off. “The same treatment, same rehabbing I’ve been doing, just staying on top of it.”

Coach Ime Udoka noted that the biggest concern with Williams at this point was getting his endurance back up to a high level after a month away from live action during his recovery.

“Physically, he is fine,” Williams said. “The wind, I don’t think, was quite there those last two games.”

Williams will continue to put in the work this week, but he knows that it will be tough to recreate his top form without actual games.

“There’s really nothing you can do to prepare to play in the NBA game,” Williams said. “You can ride the bike all you want, but it doesn’t compare. Just being out there playing, that’s really it.”