Boston starters, from left, Marcus Smart, Robert Williams III and Jaylen Brown battle for a rebound Tuesday against Sacramento. Charles Krupa/Associated Press

The Boston Celtics have been able to get their starting five at full strength for the past two games, and what a difference it has made.

With Marcus Smart returning from a six-game absence after testing positive for COVID-19, Boston’s original starting five helped open a 25-point lead after the first quarter of a 128-75 blowout win over Sacramento on Tuesday. But that game marked just the 14th time that Marcus Smart, Jaylen Brown, Jayson Tatum, Al Horford and Rob Williams were all available to start the game.

And they were at their absolute best together against Sacramento. Tatum and Brown nearly outscored the Kings by themselves with a combined 66 points. Robert Williams had a career-high 17 rebounds (seven offensive). Marcus Smart didn’t take any shots that were better off going to his efficient teammates (three field goal attempts in 24 minutes). Even a poor shooting night from Al Horford (1 of 9) couldn’t slow down the team’s momentum as the unit opened the game with a 24-7 run and added a 10-3 run to begin the second half, putting the game out of reach early in the third quarter.

“Everybody follows their lead, but they’re buying in at both ends of the court,” Boston Coach Ime Udoka said of Tatum and Brown in the starting five. “Guarding extremely well, and carrying over from the last game (Sunday’s 116-87 win over Washington) offensively is great to see, but they are the two pillars and leaders of the team, and when they come out and play with that intensity everyone seems to follow suit.

“Everyone has their role – Robert is heating up out there and Marcus is doing some of the same things, but those guys really set the tone offensively. The effort they’re giving on defense, and holding the team to 30 in this day and age in the NBA is high level defense in the first half.”

The defensive numbers have always been a strength for that starting group but reached some new heights after Tuesday’s blowout win. Among lineups that have played 150 minutes together this season, Boston’s starting five has the best defensive rating in the NBA, allowing just 91 points per 100 possessions.

The group has only played 174 minutes together over 14 games, which is a main reason why that success has not translated into much more than a mediocre record midway through the season. However, the Celtics are adamant that they are rounding into form with a clean bill of health for the time being and some overdue rotation changes from Udoka (benching Enes Freedom) taking effect with the starters providing strong play.

“Like I said earlier in the year multiple times,” Josh Richardson said. “We’ve had the most time missed with COVID, we’ve had injuries, and guys just in and out of the lineup the whole first half of the season. I would like to see the stats that show up when our whole team is healthy. I think that we’re taking that step.”

The defensive identity has reformed in these past few games as well with Smart back.

“(He’s a) steadying force,” Udoka said. “A guy who’s been doing that for a while now. It’s great to have him back, obviously, with the full roster. It feels like we can come in layers and waves so to speak with all of our guys back off the bench and guys kind of in their normal roles that they played earlier in the year. So we don’t have to rest and guys don’t have to take those breaks on the court. His defense obviously is high level but also organizationally, getting us into things that we need, pushing it with pace. The pace we played out tonight was great and he’s a huge part of that.”

BOL BOL UPDATE: Udoka said Bol Bol has been with the team in the past few days, while PJ Dozier is away rehabbing. The reason is simple: Dozier is out for the season after a torn ACL in November, while there’s a chance Bol returns this season.

Udoka said there is no timeline for Bol, who had surgery before he was traded from the Nuggets. He was traded to Detroit, but the Pistons waived the deal after looking at Bol’s medical records. That prompted Bol to have foot surgery, which Udoka said will take at least a few months to return from.

Bol will be a restricted free agent this summer. But the Celtics will get to see how he performs in practice.

Boston never traded for Bol to be a contributor this season, but at just 22, there’s some talent and intrigue.

He was one of the best prospects in the country coming out of high school, but slipped in the 2019 NBA draft to No. 44 overall.