BOSTON >> Detroit coach Monty Williams has believed it for a while, and now he has proof: The Pistons can compete with anybody in the NBA.

And, he can only hope, the wins will come soon enough.

The Pistons opened a 21-point lead over the league-best Celtics on Thursday night, forcing overtime before Boston pulled out a 128-122 victory and sent Detroit to an NBA record-tying 28th loss in a row.

“As bad as they hurt right now, I hurt for them,” Williams said. “But I told them: `If we bring that kind of toughness and execution — minus the turnovers — we’re not just going to win one game. We’re going to put something together.’”

It was the first time all season the Pistons led by more than 20 points, and the first time they had gotten to overtime in the two months since their last win. Detroit has also lost to Miami by one point, Milwaukee by two and defending champion Denver by four points this season.

“We’re on the same level as all these teams were playing against,” said Detroit guard Cade Cunningham, who had 31 points and nine assists but missed a potential winning 3-pointer at the end of regulation.

“There’s no team that I’ve ever come across in the NBA where I felt like I was going into a slaughterhouse. I’ve never felt like that in my life, going into a basketball game,” he said. “So every game we should be able to fight teams and impose our will on them. We did that early on. We kind of let go of the rope a little bit in the third quarter. But there’s a lot of growth, and something we can learn from and definitely take to the next game.”

Detroit fell to 2-29 and matched the “Trust the Process” Philadelphia 76ers with the 28 consecutive losses; the Pistons need a victory at home against Toronto on Saturday night to avoid breaking the NBA record for longest losing streak.

In major North American sports, only the NFL’s Chicago Cardinals, who lost 29 straight from 1942-45, have had a longer losing streak.

“I’m not interested in just winning one more game this year — you know what I mean? To stop this. That would be soft, in my opinion,” Cunningham said. “Our goals are a lot higher than that. We have what it takes to win a game, that’s nothing. But to put games together, to find our system, find what’s clicking and allow us to sustain winning. That’s all we’re looking for.”

Kristaps Porzingis had eight of his season-high 35 points in a 10-0 run that turned a four-point deficit into a 106-100 Boston lead in the final two minutes of regulation. Jaden Ivey scored six straight points for Detroit to tie it.

Then, after Jayson Tatum was credited with a layup on a replay-confirmed goaltending call, Bojan Bogdanovic made a putback on Cunningham’s missed 3 to send it to OT.

Derrick White scored 10 of his 23 points in the extra period and Porzingis had six in the overtime — dunking after a full-court pass from Tatum and then sinking a pair of free throws to make it 125-117.

Tatum had 31 points and 10 assists for Boston, which won its fourth straight and its ninth in the last 10 games. The Celtics, who were without Jaylen Brown, are 15-0 at home this season and have the league’s best record, 24-6.

The Pistons set the NBA record for most consecutive losses in a season Tuesday night with their 27th in a row, a 118-112 loss to Brooklyn. The Sixers’ streak stretched over two seasons, 2014-15 and 2015-16.

“I’m unbelievably proud of the group, the way they bring it,” Williams said. “They’ve heard all the stuff about our team and they just keep bringing it. I know it’s going to pay off.”