After Al Horford won the opening tip of Game 1 of the Eastern Conference Finals, Jaylen Brown corralled the ball while fending off Cleveland Cavaliers sharpshooter Kyle Korver. Brown controlled the orange with his left hand — his right was occupied with Korver — and immediately beamed into attack mode with George Hill as the only obstacle standing between him and the hoop.

Then, with a deceiving start-stop dribble, he turned Korver and Hill into frozen blocks of ice and zipped to the rim for a left-handed layup. The scoreboard on the bottom of ESPN's broadcast had only flashed onto the screen moments earlier, but the Celtics launched the scoreboard operator into action, already holding a two-point advantage.

That initial score, despite occurring just five seconds into the game, would be a glimpse of things to come. Horford, a veteran, sparked the play while Brown, one of the youngsters plucked from Boston's treasure chest of lottery picks, finished it off as the duo led Boston to a 108-83 route.

Brown dropped a cool 23-8-1-1-1 on 9-of-16 shooting while pouring in three long-range bombs on five attempts. Horford, as always, was the steady presence keeping the offense spinning with 20 points (8-of-10 shooting, 2-of-4 from deep), six assists, four rebounds and two blocks. That combination of veteran savvy and youthful intrigue is exactly what makes Boston a burgeoning title contender — even if they're not quite ready this year.

Jaylen Brown, Celtics
Original Photo: USA TODAY Sports

Once a healthy Kyrie Irving and Gordon Hayward reenter the fold, the Celtics will sport a trio of experienced All-Stars to mesh with their young core of Brown, Jayson Tatum and Terry Rozier among other rotational players. Oh, and they own first-round picks in this year's upcoming draft.

But enough about the future. The Celtics have a legitimate chance to make their first Finals appearance since 2010 now. On Sunday afternoon, the Brown-Horford tandem were the two best players on the floor — a court they shared with LeBron James.

Brown's leap to becoming this type of impact player wasn't supposed to materialize this quickly, especially considering the eyebrows Celtics general manager raised when he selected Brown third overall in 2016. Hayward's absence has accelerated his maturation, but what's been most surprising is his emergence as a legitimate deep threat, adding a three-point presence to his slashing offensive game.

In his lone year at Cal, Brown was just 30 of 102 (29.4 percent) beyond the arc; as a rookie, Brown shot 34.1 percent; this season, he nailed 39.5 percent of his looks from downtown; through 13 postseason tilts, he's converted 42.9 percent of those attempts. Perhaps the biggest reason for his growth is a tweak in his shot mechanics. Take a look at this attempt during his time in Berkley:

Note how it's almost two-step process. He raises the ball above his head and then launches. Contrast that to his makes from Sunday's game and the alterations are minor yet noticeable and effective:

Absent is the windup in Brown's form on those shots and the release point is in front of his face as opposed to above the head. It's fluid, smooth, and unlike the previous clip, it isn't a catapult-like approach, which can often lead to ugly misses sprinkled around the rim.

The second-year wing is even holding his own on pull-up triples, converting a combined 14 of 40 (35 percent) between the regular season and playoffs this year. Last season, Brown was just 1 of 16 off the bounce.

His running mate from Sunday, Horford, continued to prove that, despite his 32nd birthday drawing closer every day, a decline is nowhere imminent. As a scorer, he overpowered the Cavs' small-ball center Kevin Love:

But Horford also possesses the quickness to zoom past Love, which became problematic in pick-and-roll and pick-and-pop sets:

Therein lies the problem for Love in this series. Against the Raptors in the second round, even when Toronto's ancient center, Jonas Valanciunas, punished Love on one end inside, Love could simply pull him out to the perimeter and burn him on back cuts, pick and pops or spot-up opportunities. Love can't leverage his speed into scoring chances against Horford because such a disparity in quickness doesn't exist.

Celtics, Al Horford
Original Photo: USA TODAY Sports

He's outmatched on both ends of the court and it leaves Cleveland with one true star. That enigma is why Cavs head coach Tyronn Lue is considering inserting Tristian Thompson into the starting unit. Such a move might also help to unlock Love, who's a natural power forward and has been vocal about his preference to play the 4-spot, but has soldiered on at center for the good of the team.

Indiana pushed Cleveland to seven games in large part because LeBron was the only reliable option as Love struggled mightily against Thaddeus Young's length and quickness while battling a torn ligament in his left thumb. In the second round, Love was the better 5-man and the Cavs cruised to a four-game sweep.

As The Ringer's Kevin O'Connor noted, the Celtics are also eliminating Love's chances to post-up undersized guards and wings, something he feasted on during the previous round, by switching defensive assignments while the entry pass hangs in the air:

Horford and Brown were brilliant on Sunday, but they weren't alone in their efforts. Tatum chipped in 16 points (6-of-11 shooting, 2-of-5 from deep), six rebounds, three assists and two steals; Rozier, despite a shaky shooting night (4-of 10, 0-of-3) posted an 8:1 assist-to-turnover ratio and snared six boards; Marcus Morris slid into the starting lineup and tallied a double-double with 21 points (7-of-12, 3-of-4) and 10 rebounds.

The Celtics were left for dead weeks ago. They shouldn't be here, three wins away from their 22nd NBA Finals appearance. But, they are, spearheaded by a fusion of veteran leadership and youthful ignorance. Sunday's stars, Al Horford and Jaylen Brown, encapsulate that fact.

This postseason has simply been a glimpse into the potential that awaits Boston next year when its veteran star power expands, primed to meld with young studs and produce a championship-caliber squad.