Jaylen Brown‘s insertion as a Boston Celtic starter came, in some ways, at an inauspicious time.

In the wee hours of January 25, not long after midnight, the Celtics boarded a plane near Washington, D.C. The late flight home was quiet.

The team had just finished up on the losing end of a 123-108 score. The Wizards arrived that night dressed in all black. It was the famous “funeral game.” And they carried through on their swag, at least in this regular season contest.

Bradley Beal and John Wall combined for 58 points against the Celtics, who were still without the services of Avery Bradley.

“My only satisfaction from this game,” one wag wrote on the next-day Celtic thread at reddit.com, “came from the half-filled Wizards stadium.”

At 26-18, the Celtics seemed headed for another season of modest improvement, but not necessarily a lot more.

True, they had been without the services of Al Horford and Isaiah Thomas in a number of losses. Then again, teams like Cleveland and Toronto had been without one or more key starters for a substantial stretch.

Coming off three straight losses (including home losses to the Knicks and the Trail Blazers), the Celtics loss to the Wizards made things seem, well…. a little dark.

Bradley was likely to miss at least another month. Fans fretted, “what does sometime in April mean?” Things could have gone south fast.

“At least there was Jaylen Brown,” another redditor wrote, hopefully.

Indeed, Brown’s season was about to get a jump start, and so was Boston’s.

ABOUT 16 HOURS after de-boarding at Logan, the Celtics began arriving at the Garden to dress and warm up for a game against Houston.

Not long before game time, the team announced Brad Stevens was going to start Brown — along with fan fave Jonas Jerebko — against the Rockets.

Masslive, in an apt preview minutes later, wrote:

“It will be interesting to see which Celtic draws the assignment of guarding James Harden. Crowder has the size, but he is usually more useful against bigger wings.

“Jerebko and Thomas, for opposite reasons, obviously won’t receive the assignment. That could mean that Brown, just a rookie, might be thrown to the wolves and given a chance to fight his way out. Guarding Harden would be a real test, and it might get Brown in foul trouble quickly, but that would be an intriguing plan.”

Brown didn’t end up spending a lot of time on Harden. He played only 13 minutes as he picked up four fouls (three of them offensive, interestingly.) He ended the night with one basket, three rebounds, and three turnovers.

But in Brown’s first eight minutes of play, Harden hit only one field goal… along with two free throws after drawing Brown’s lone defensive foul of the game.

For the game, Harden shot 6 of 18, but added 16 of 19 free throws, ending with 30 points and 12 assists in a 120-109 Celtics win.

Brown’s offensive coming out party would have to wait. For a couple nights, anyway.

ON JANUARY 27 against the Magic Brown showed flashes of the athleticism that led the Celtics to select him with the third pick of the 2016 NBA draft.

“For the second straight game, a version of Brad Stevens’s new starting lineup pushed the team to an early lead,” Mass Live wrote.

With Brown tossing in 9 first quarter points, the Celtics raced to a 39-24 advantage in the first 12 minutes. They rolled to an easy 129-98 win. Jaylen Brown finished with 20 points, and one turnover. He also led the Celtics with 8 rebounds in just over 30 minutes of play.

The Bucks stop here

JANUARY 28 in MILWAUKEE, the Celtics arrived for another back-to-back.

Brown had a so-so night offensively, scoring 9 points. His 8 boards, though, once again led the rebound-starved team.

Brown got “rooked” on at least one call, pictured nearby. (Feisty Bucks guard Matthew Dellavedova appeared to get more than a little arm. But, well, there’s a reason they call it “getting rooked.”)

Brown’s contribution down the stretch proved critical.

With 3:38 to play and Boston clinging to a 97-95 lead, Brown stole the ball from rookie of the year Malcolm Brogdon. He coasted for a layin with 3:33 to give the Celtics a 99-95 lead.

Brown’s 3-pointer a minute later put the Celtics up 102-97. These were the last points they would score in regulation. Thanks in part to Brown’s clutch baskets, they made it to overtime for a 112-108 win.

Brown chipped in modestly in victories over Detroit (4 points) and Toronto (8). But with the win over the Raptors, the Celtics pushed their record to 31-18. Boston was closing in on a coaching spot for Brad Stevens in the NBA All-star game.

SUDDENLY THE CELTICS were riding a 5-game winning streak. And heading into a home matchup against the team every Celtics fan likes to put an “f” in front of, the LA Lakers.

February 3 — Brown turned in a 12-point, 7-rebound performance as the Celtics won 113-107.

For the third straight game, he had no turnovers. This gave the rookie a total of 5 miscues in 6 games as a starter in the Celtic turnaround run. (Three came in his January 25 start against Houston.)

Brown followed that up with another solid night against the Clippers on February 5. He scored 11 as part of a lineup that held J.J. Reddick, Austin Rivers, and Paul Pierce to a combined 14 points.

On a so-so shooting night — 4 of 10 from the floor, 1 of 5 from 3 — Brown left the game with just under 4 minutes to play and the Celtics in front, 97-85. (Pierce hit a late “gentleman’s contested 3” that ignited the Garden into a well-deserved uproarfaithful.)

THE CELTICS THEN took to the road February 8 for what would turn out to be their only loss during the run. An embarrassing 108-92 defeat on at the hands of the Sacramento Kings — who were playing without Boogie Cousins.

(This game, reportedly, was a factor in convincing Kings ownership to finally deal Cousins. They did so days later, over the all-star break. Shoutout to Bill Simmons and “the Ewing theory.”)

Brown didn’t play well. He put up 6 points, 3 turnovers. Neither, of course, did most of the Celtics. Matt Barnes and Willie Cauley-Stein went crazy off the bench and on the boards. The Kings ran Boston out of the gym in the fourth quarter.

As the team boarded the plane for a back-to-back on the west-coast road trip, however, the Celtics were about to show they could turn things around.

Blazing a clutch trail

February 9 — The rookie notched 14 points, and 7 rebounds (tied for team lead). The Celtics won 120-111 in Portland.

As in the Milwaukee game, Brown was about to show what he could do down the stretch.

With just under four minutes remaining, the Celtics led 102-100. Isaiah Thomas missed a three point shot that would have given Boston a 5-point lead. Then Brown grabbed the rebound and converted. After the flurry, the Celtics led 104-100.

With 2:10 to play, and the Celtic lead back down to two, Brown drew a foul by C.J. McCollum. He sank both free throws. Boston 108, Portland 104.

After a Marcus Smart basket put the Celtics up by 6, Brown drew a foul by Damian Lillard. Brown converted two more charities for a 112-104 lead with 1:12 to go, sealing the win.

As the Celtics took off for Utah, the Boston and national press began casting emoji ogle eyes. MassLive.com noted Brown’s mean spirited (in a good way) post-up game (nearby). NBA writer Zach Lowe noticed the trend and gushed about it on ESPN.com.

The “Lowe post”

“With Jaylen Brown starting and Avery Bradley out, Brad Stevens’s rejiggered rotation occasionally lands on lineups featuring Brown, Jae Crowder, and Jonas Jerebko. It’s a funky small-ball trio that works better than you’d think.

“Boston is a whopping plus-32 in the 85 minutes these guys have shared the floor, per NBA.com. Brown looks shockingly comfortable as a starter. He’s a violent slasher with a mean-spirited, butt-first post game to deploy against smaller defenders. He is playing with more control than he showed during a wild first few months. Crowder is quietly shooting almost 42 percent from deep, and Jerebko makes the right play every time.”

Brown suffered a hip flexor injury on February 11 in Utah. The injury that would nag him off and on for the rest of the season.

But as the Celtics savored their 112-104 win over the Jazz and prepared to close out the road trip in Dallas, they were on a roll. From 26-18 when they sunk into their seats after the Wizards funeral game, they were now 35-19.

Hinge-point — “Brown delivers”

The Celtics were winners of 9 out of ten, all with Brown as a starter. Four of the 10 were road games, 6 came against eventual playoff teams.

Jaylen Brown certainly wasn’t the star or leader of the team during the turnaround. That said, he helped the team bounce up from a 3-game losing streak, and get back to winning in the absence of Avery Bradley.

Brown’s moments in crunch time (Milwaukee, Portland) and overall play in close wins (Lakers, Clippers) were a key part of the story.

Boston was starting to close in on Cleveland (37-16) for the “fake #1 seed” in the east.

And although he missed the next 3 games (during which the Celtics went 2-1), Brown’s contribution as a starter and in clutch moments wasn’t finished.

Part Two here

(Discuss Jaylen Brown’s rise to starterdom at our reddit thread.