BOSTON -- Before his Boston Celtics took on the Golden State Warriors on Saturday night, Brad Stevens was asked about the task of taking on the two-time defending champions.

"They have a lot of highly skilled, highly intelligent basketball players that, if you take your foot off the gas for one second, you're dead," Stevens said. "They make you play possession to possession, they make you have that kind of focus, and that's really good to see where you're at at a given time.

"So that's what I'm looking forward to tonight: seeing where we are at."

A few hours later, after the Warriors emerged from the cauldron of energy that was TD Garden -- aided by extra imbibing thanks to an 8:30 p.m. ET tip, plus the presence of New England Patriots owner Robert Kraft and several players ahead of next week's Super Bowl -- with a 115-111 victory over the Celtics, Stevens had his answer.

No, the Celtics didn't win. And no, a team that was expected to face the Warriors in June's NBA Finals before the season began is not in the business of taking moral victories out of any regular-season game. But the Celtics gained something from Saturday's defeat: further clarity on what this team needs to be to reach its potential and what, so far, is holding it back from doing so.

"I think we know the level [we have to get to]," Marcus Morris said. "We just have to get to it."

Brad Stevens' Celtics had a chance to beat the Golden State Warriors at home on Saturday, but Kyrie Irving couldn't quite get Boston a lead in the game's last two minutes. Jesse D. Garrabrant/NBAE/Getty

This game played out in precisely the manner the Celtics would've hoped beforehand: with the score tied in the final minutes, allowing Boston to give the ball to its closer, Kyrie Irving, and let him try to carry the Celtics home.

Irving, as he has been all season, was outstanding in this one, finishing with 32 points and 10 assists and completing a pair of ridiculous finishes late in the fourth -- once finishing with his left hand over Klay Thompson and once putting on a dizzying dribbling display before finishing with his right over Andre Iguodala.

Against the Warriors, though -- with their length and athleticism all over the court in their closing lineup allowing them to switch liberally -- Boston showed how overly reliant on Irving it is in those situations.

After Irving's layup over Iguodala tied the game at 108 with 2:43 remaining, he lost the ball while trying to force a dribble move into the lane on the next possession, setting up a Klay Thompson 3-pointer that put Golden State ahead.

On the following possession, Al Horford tried to force the ball to him, causing yet another turnover.

"They do a great job of switching," Irving said. "They try to keep you away from the paint and make you take tough shots. We converted on a lot of them tonight. Some teams struggle with that, but we had our opportunities. We just got to finish them when we see them in Golden State."

Some of those finishing issues, as Irving pointed out, were because of Golden State's switching. But it also was emblematic of the fact that, in the final minutes, the Celtics lack another clear option to go to if he is bottled up.

Marcus Morris, who had been so reliably hot through the first two months of the season, has finally cooled off in January. After going 3-for-12 from the floor and 2-for-6 from 3-point range -- including a potential go-ahead 3-pointer with 10.8 seconds left -- he's shooting 40.3 percent from the field this month.

Jayson Tatum, meanwhile, had a hot third quarter, scoring 14 points, but he recorded just six points in the other three combined and remains prone to taking the kinds of contested midrange jumpers that the basketball world has learned are the sport's worst shots.

By design, the player who should be Irving's late-game sidekick is Gordon Hayward. But this was another performance he would undoubtedly like to forget. Hayward missed all five shots he took, scoring two points to go with seven rebounds and two assists in 22 minutes -- further highlighting the fact that, if the Celtics are to reach their potential, Hayward has to return to his pre-injury form.

It also was a very real -- and sobering -- reminder that, despite there being another three-plus months before the Celtics will need that version of Hayward to arrive, there's no guarantee that he'll be there by then.

The same could be said for Terry Rozier, who had one enormously positive play -- skying through the air to collect a missed Hayward 3 and lay it in to tie the game at 96 with 8:27 remaining -- and otherwise struggled to make an impact, as he has much of the season. Rozier, who will be a restricted free agent this summer, has been playing like someone who is trying to rush all of what he's capable of doing into the 15-20 minutes per night that he is getting, as opposed to the 35 minutes per game he saw last season's playoffs, when Irving was sidelined with an injury. Tonight was another example of that.

The struggles from both of them -- not to mention center Aron Baynes, Boston's typically rock-solid backup center who was made into a turnstile defensively by Golden State in his first-half stint -- allowed the Celtics, despite having far more firepower coming off the bench, to be outscored 17-16 by Golden State's second unit.

Missing Clovers Boston's depth is a key component to the team's contender status. But the offensive firepower wasn't there in the second half of a two-point home loss for the Celtics. Celtics bench 2nd-half minutes 2nd-half points 2nd-half FG Gordon Hayward 9:25 0 0/3 Jaylen Brown 10:05 0 0/2 Terry Rozier 9:31 2 1/3 Aron Baynes DNP* N/A N/A Daniel Theis 3:42 0 0/0 *Celtics were outscored by 11 points during Baynes' 9:40 minutes in first half

Horford, on the other hand, once again looked like the player who was the best -- non-LeBron James division -- in the Eastern Conference playoffs last year. Horford finished with 22 points, 13 rebounds, three assists, a steal and two blocks in 34 minutes, looking spry and moving around the court with ease as he had his way with DeMarcus Cousins whenever they shared the court. The only blemishes for Horford: no free throw attempts and a season-high five turnovers.

Horford has dealt with nagging knee tendinitis this season, and it has shown; depending on the nights, scouts say either Horford looks creaky or he looks like his usual All-Star self. None of that is especially surprising, given that he's a 32-year-old big man in his 12th NBA season. But it is this version of Horford that easily won his matchup with Philadelphia 76ers star Joel Embiid in last year's playoffs and the same one that Milwaukee Bucks center Brook Lopez will struggle mightily to stay in front of if those teams meet this spring.

While Horford isn't on Irving's level, he is, inarguably, the most irreplaceable Celtic. Boston doesn't have another big man who can come close to doing what he can at both ends.

"I just think that we can play with anyone," Horford said. "It was nice to go out there and compete in that way, give ourselves a chance to win there at the end.

"They're the team to beat. Those guys, they really understand how to play. They know each other's strengths and things like that. They play really well, so you have to play almost a flawless game to beat them."

The Celtics didn't do that, committing a season-worst six of their 14 turnovers in the fourth quarter -- not including Marcus Smart's not being in position (due to slipping or simply overrunning the ball, depending on one's vantage point) to corral a second straight missed Draymond Green foul shot with eight seconds remaining. That allowed Green to secure the ball and get it out to Stephen Curry, who then hit two free throws to ice the game.

It was an imperfect game from an imperfect team -- but, also, a clarifying one.

The Celtics learned Saturday night what they are. They also learned just how far they are from where they need to be if they want to host the Warriors at TD Garden again this season.