BOSTON – Former Boston Celtics coach Doc Rivers used to talk all the time about wanting to have “agitators” on his roster, the kind of players that always seemed to find a way to get underneath the skin of opponents.

Rivers is gone, but the Celtics still have a few – quite a few – agitators around. And their ability to get underneath the skin of opponents has been a major factor in Boston’s ascension up the Eastern Conference standings.

Monday’s 111-95 win at Houston was Boston’s third straight, and fourth in the last five games. Several factors have worked in Boston’s favor during that stretch, with few standing out as much as the team’s ability to just work the nerves of their opponents.

“This group is relentless,” said Boston’s Isaiah Thomas. “Guys don’t care how anybody feels. We’re gonna be right there at all times in your face.”

And that brand of basketball has worked quite well of late with the Celtics (6-4) off to their best start to the season under third-year coach Brad Stevens.

But the last three victories have been impressive not only because of the caliber of opponent (Atlanta, Oklahoma City and Houston), but the manner in which the Celtics have gone about disposing of those teams.

“We play hard,” said Boston’s Jae Crowder. “Guys don’t like that in this league. Guys want an easy flowing game. But we play hard and a lot of guys don’t like it. I can say that.”

There was a point in Sunday’s win at Oklahoma City when Russell Westbrook was on the ground, with the ball in hand while players stood around. Marcus Smart didn’t hear a whistle, so he lunged at Westbrook to try and take the ball away.

The Thunder didn’t like this.

Last night, the Houston Rockets got more of the same physical treatment from the Celtics.

And like the Thunder, they too got ran out of the gym by the surging Celtics who have beaten their last three opponents all by double digits.

There was only one other stretch since Stevens became the Celtics’ head coach in 2013 (Dec. 15-19, 2014) in which they won three consecutive games – all by double figures – by an average of 14.7 points. But the latest three-peat by Boston is far more impressive than those three wins in 2014 which came over lottery-bound clubs Philadelphia, Orlando and Minnesota.

If the Celtics continue to play as they have of late, their reputation as a gritty squad that will try and work you over both physically and mentally, will only grow.

“We want that to be our rep,” Thomas said. “‘Damn we got the Celtics tonight. They’re gonna give it their all.’ We just have to continue to work, continue to get better out there.”

And it starts with defense, something Celtics head coach Brad Stevens has talked about as an absolute necessity in the DNA of this team in order for them to be successful.

Players have taken his words to heart and are starting to show a greater sense of understanding what they need to do as a collective unit defensively. And that has made for some uncomfortable floor time for opponents.

“You usually have one or two guys not on the same page (defensively),” Crowder said. “It’s a beautiful thing when all five guys are so locked in and all on the same page, all playing for one another. It’s a beautiful thing.”

It is … unless you have to play against them.

It will surely lead to some combustible moments on the floor. On more than one occasion against the Thunder, officials had to have a word with Marcus Smart and Russell Westbrook who were jawing with one another at times.

And in Monday’s win at Houston, there was an incident in the third quarter involving Amir Johnson and Rockets forward Terrance Jones that ultimately led to Jones, Isaiah Thomas and Houston All-Star James Harden each being whistled for a technical foul.   

“We’re a very aggressive team and we’re not backing down from anybody,” Smart said. “With that being said, it’s going to be some chippiness out there.”

Which slowly but surely, is becoming something opponents should expect to face when they play the Boston Celtics.

“When teams come and play us, they know we’re going to get into them defensively,” Crowder said. “We’re starting to build that DNA.”

Spoken like a true agitator.