Here’s what has gone right in the Celtics’ best stretch of the season

ORLANDO — On Jan. 21, the Celtics were held without a field goal for the final seven minutes of their game against the Trail Blazers and coughed up an 11-point lead and lost. That setback sent the team back below .500, igniting questions about whether president of basketball operations Brad Stevens should essentially surrender this season and shift the focus toward the future in advance of the Feb. 10 trade deadline.

Since then, however, the Celtics have shown that they should not be counted out just yet. Boston (29-25) has won six of its last seven games and entered Saturday night in eighth place in the East, just one game behind the sixth-place Nets and five games back of the first-place Bulls.

“Just got sick of losing, I guess,” center Robert Williams said. “Sick of going out like that, sick of having the disgusting taste in your mouth.”

The Celtics are hardly title contenders, but they have shown that they do not plan to simply crumble. Here’s a look at what’s gone right during their best stretch of this mercurial season:

▪ The opening lineup. It all starts with the starters. Boston’s five-man unit of Jayson Tatum, Jaylen Brown, Marcus Smart, Al Horford, and Williams has been elite. The problem was that prior to this recent uptick, the starting group had been whole for just 12 games.

Over these last seven games, this lineup has been devastating, outscoring opponents by an average of 36 points per 100 possessions in 93 total minutes.

“Defensively with that group, with the way that we fly around out there, I feel like we’re always going to be in a good position,” Horford said. “I think the other part for us is figuring out offensively how we can make it work, and starting with Jayson and Jaylen, it’s been working really well.”

▪ Marcus Smart’s impact. This hot streak has coincided with Smart’s return following a bout with COVID-19. He has been excellent during the stretch, averaging 11 points, 6.6 assists, and 3.7 rebounds in 29 minutes per game. Smart has been an efficient scorer, shooting 54.9 percent from the field overall and a remarkable 81.8 percent from 2-point range, including an array of acrobatic finishes and difficult floaters.

Smart said that in addition to getting over COVID, he is finally fully recovered from a calf strain he suffered midway through last season.

“I’m able to explode and get back to myself,” he said. “That’s really it. A lot of the time I couldn’t explode off it, jump, and really get to the rim like I wanted to.”

Boston has a plus-31.2 net rating with Smart on the court over the last seven games.

▪ Confidence in rotations. The starting lineup has been excellent, but that’s also created a trickledown effect. Earlier this season, the roster was so battered that journeymen such as Joe Johnson, C.J. Miles, and Al-Farouq Aminu were signed to 10-day deals, and the Celtics’ regular end-of-bench players were pressed into significant roles. That dented the search for continuity and made it challenging for coach Ime Udoka to settle on preferred rotations.

Now, there is more consistency. Udoka has mostly been leaning on a condensed, eight-man rotation that features Grant Williams, Dennis Schröder, and Josh Richardson off the bench. Schröder has had a few rough patches and has generally been more effective as a starter, but Richardson and Grant Williams have provided defensive versatility and long-range pop. Over the last seven games they are shooting 48.1 and 44 percent from the 3-point line, respectively.

“We’ve [had] so many guys out that so many people on our team have had to pick up other responsibilities in games and play more or less minutes, and do different things,” Richardson said. “But I think we found some continuity and what we’re going to have to bring to the table every night.”

▪ Holding leads. On Jan. 6, the Celtics coughed up a 25-point advantage and lost to the Knicks, the most embarrassing botched lead in a season that has had plenty. But the Celtics have been incredibly consistent during this seven-game stretch. They never trailed in victories over the Wizards, Heat, Pistons, and Kings, and briefly fell behind, 2-0, in the win against the Pelicans, and were never behind after that.

The Celtics are not even giving teams time to think about big comebacks.

“Earlier in the year, we would get leads like this and lose them,” Robert Williams said. “Obviously, teams are going to go on a run, but I think we are doing a great job of keeping our composure to a certain extent, responding to their runs.”

▪ Matchup luck. The Celtics dealt with their own health issues, so they know what it’s like, but it’s worth pointing out that this recent surge has come against teams that are not very good, or not close to full strength, or both.

Four of the six wins were over teams with losing records, and the opponents’ absences have been significant. The Heat were missing starters Kyle Lowry, Jimmy Butler, and P.J. Tucker. The Pelicans were without perhaps their two best players in Brandon Ingram and Jonas Valanciunas. The Kings did not have star guard De’Aaron Fox. Gordon Hayward was out for the Hornets. No. 1 overall pick Cade Cunningham was sidelined for the Pistons.

The challenges will remain simplified during the rest of this trip. After facing the 12-win Magic on Sunday, the Celtics will visit the Nets, who will be without starters Kevin Durant, Kyrie Irving, and Joe Harris.

▪ The defense is thriving. Udoka has said throughout this season that this team’s identity will be its defense. The Celtics had shown flashes of dominance at that end of the floor but struggled to do it consistently. Over the last two weeks, however, they have been a wall.

Boston has a league-leading 96.5 defensive rating since Jan. 23. To put that mark in perspective, Golden State’s 103.5 defensive rating leads the NBA.

Opponents are shooting a league-low 38.2 percent from the field during this stretch. The Celtics also have done a good job of keeping opponents off the foul line; their .206 free throw rate ranks fifth in the league.

“One thing we’ve stressed is letting our defense turn into offense, and stops causing turnovers, getting easy baskets,” Udoka said.