Celtics pose stiffest challenge yet to Nets

The Nets will host an understandably confident bunch at Barclays Center on Tuesday.

After starting the season 0-2, the Celtics have won 12 consecutive games, toppling the Bucks, Spurs, Thunder and Raptors along the way.

The last time they suffered a defeat? October 18 — 27 days ago. The last time the franchise rattled off such an impressive run? The 2008-09 season.

“It’s unbelievable [what they’ve been doing],” coach Kenny Atkinson said. “They have a lot of talent, a lot of athletic talent. And then they have [Al] Horford and [Kyrie] Irving to kind of steer the ship. That to me is almost a perfect formula. You got two All-Star type players — vets — and then you have a young crew that’s learning around them, and an established system. It’s a pretty good recipe for success.”

And next on Boston’s list of potential casualties is the D’Angelo Russell-less Nets.

“The Celtics are probably playing the best basketball in the NBA right now,” said Spencer Dinwiddie, Russell’s replacement in the starting lineup.

Boston is in first place in the East and most recently beat the Raptors, 95-94, without Irving, who suffered a minor facial fracture in a victory over Charlotte on Friday. The star point guard will travel with the team to Brooklyn and has been upgraded to questionable.

Rookie center Jarrett Allen returned to practice Monday after missing time with a foot injury.

Following the session, the big man said he felt some pain but that was to be expected. He is listed as questionable for Tuesday.

Asked what he did to get through the setback, Allen responded with a laugh: “I would say just Philly’s philosophy — trust the process. Trust what the trainers are doing. If you listen to them, you can’t really go wrong.”

The 19-year-old has appeared in six games, and is averaging 4.0 points, 2.7 rebounds and a block in 15 minutes.