PHILADELPHIA – These Celtics are just so… Celtics.

And they’re proud of that fact.

Boston is a historic franchise whose teams are known for displaying pride, effort and teamwork. This year’s team is no exception, and those traits are aiding its ability to shock the world during the NBA Playoffs.

“When I put on this green jersey with ‘BOSTON’ on the front of it, there’s a lot to live up to,” said center Aron Baynes, “and you want to try to add to the legacy that is there already.”

The legacy consists of an NBA-record 17 titles. It includes a plethora of Hall-of-Fame players and coaches. It features 22 retired numbers.

This season, the story continues to evolve, as the 2017-18 Celtics are writing their own chapter in the franchise’s history book.

Boston lost arguably its two best players this season in Gordon Hayward and Kyrie Irving, one at the start of the season, and one during the final month of the season. Two of the team’s top players, Jaylen Brown (21) and Jayson Tatum (20), are 21 years old or younger. The team’s starting point guard, Terry Rozier, had been a backup for the first two and a half seasons of his career before being thrust into the starting lineup once Irving went down. Three other rotational players are either inexperienced in postseason play (Marcus Morris and Shane Larkin) or rookies (Semi Ojeleye).

Yet on May 6, one day ahead of Game 4 against the Philadelphia 76ers, these Celtics are on the doorstep of the Eastern Conference Finals with a 3-0 series lead.

If they manage to reach the next round, it will mark one of the most improbable runs to the Conference Finals in NBA history. In Marcus Smart’s words, “That would be a Cinderella story for us.”

Smart went on to elaborate on why this run could become so special.

“It would be a big, big, big deal (to reach the Conference Finals),” he said, “obviously with the history and just that we’re doing this with all young guys and minimal experience in the Playoffs and without, what people say, are our two best players.”

The story is only sweetened by the fact that the team is reaching these unexpected heights by channeling its inner-Celtic Pride.

“We’re playing for the name on the front, not the name on the back,” Smart said.

They’re also playing one game at a time, and refusing to look ahead.

Every time Smart spoke about his team contributing to the legacy of the organization, he finished the sentence by honing in on Monday’s Game 4.

First, he said: “That would be a Cinderella story for us. But we’re not focused on that.”

Next, he said: “Obviously it would be a big, big, big deal, obviously with the history and just that we’re doing this with all young guys and minimal experience in the Playoffs and without, what people say, are our two best players. But right now we’re focused on Philly and the next game.”

The rest of his teammates have the same mindset. That’s how this team and this franchise operate.

There’s a long way to go until the Conference Finals. Everyone knows that. The Celtics still need to log one more win against a very talented and capable 76ers team. There are no guarantees.

The only sure thing at this point is that this Boston team will play with pride, effort and teamwork Monday night, and every other time it takes the court. This team is built with Celtics DNA.