BOSTON -- When the Boston Celtics opened the doors to their practice facility at the end of Tuesday's off-day workout, the largest throng of TV cameras they'd seen this season rushed to set up shop on the floor. There was an obvious buzz ahead of Boston's impending showdown with the Cleveland Cavaliers, and Wednesday's game was a chance for Boston to finally assert itself as a legitimate challenger to the Cavs' throne.

While most Boston players downplayed the matchup, veteran Avery Bradley, the only Celtics player remaining from the last time Boston won a playoff series, noted, "We're playing against a team that's obviously going to be a contender. It's our job to go out there and make sure we're setting our mark now, showing them how we are going to play, so if we do meet up in the playoffs, they know what to expect."

Thirty hours later, the Celtics hit the floor impossibly uninspired. They got outworked to every rebound in the first quarter, struggled to generate offense when Isaiah Thomas was off the court in the second, failed to routinely get back in transition throughout the night and were absolutely shredded by LeBron "I'm The Last Person To Ask About A Regular-Season Game, Dude" James as the Cavaliers posted a 114-91 triumph at TD Garden.

With the victory, the Cavaliers took a commanding lead in the race for the No. 1 seed in the East, moving a game up on Boston while being further aided by owning the head-to-head tiebreaker. The way Cleveland dispatched Boston only cements the notion that the Cavaliers are capable of simply flipping a switch when they want to and are unlikely to be challenged by someone out of the East.

The Celtics found themselves lagging behind the Cavaliers yet again Wednesday. David Butler II/USA TODAY Sports

"We were lucky it wasn't worse," offered Celtics coach Brad Stevens.

Added Thomas: "[The Cavaliers] were on a different level than us tonight. They played harder than us in every aspect of the game. ... It's very disappointing. We laid an egg tonight. There's no way around that."

For the Celtics, frustrations with Wednesday's loss run deeper than a poor outing in front of a national audience. This was yet another instance this season in which a Boston team with a bit of momentum shrunk while facing top competition. Each time this team puts itself in position to leap into the spotlight, it finds a way to slip back down the East grease pole.

"We need to stick together. We need to play with more purpose," said Bradley, who admitted the Celtics got "exposed" in Wednesday's loss. "It was a playoff atmosphere, and we understand that we need to play better than we played tonight. We have to move the ball. We have to trust each other. We have to talk on both ends of the floor. Those are things we know. We just need to move on and focus on the next game."

Bradley suggested that Wednesday's loss could bring the Celtics closer together and offers a reminder that this team isn't where it needs to be in order to truly be competitive in the postseason. Celtics players embraced the fact that they have another national TV tilt on Thursday in Atlanta.

But here's the sobering reality: The Celtics are 4-8 against the other top-three playoff teams in the East and 29-6 against the rest of the conference. Despite its glossy record, Boston hasn't consistently shown itself capable of consistently beating the sort of top competition it will face after the first round of the postseason.

The Celtics still have work to do to secure the No. 2 seed, but that remains their most likely landing spot. They are back below the radar, a spot that they tend to thrive in, but at some point they must step forward and show they can embrace the limelight.

It hasn't happened this season.

There was that late December visit to Cleveland in which Boston had won six of its previous seven games and Thomas was emerging as the king in the fourth. Despite a lackluster performance by James, the Cavaliers still rolled to a 128-114 triumph.

Boston rebounded by winning four in a row, then headed north to Toronto with a chance to pull even with the Raptors. Boston had a double-digit second-half lead but watched DeMar DeRozan will Toronto back for a 114-106 triumph.

BOSTON CELTICS Check out the team site for more game coverage CLEVELAND CAVALIERS Check out the team site for more game coverage

There was the funeral-game loss in Washington. They quite literally kicked away a win in Phoenix, rebounded to beat Golden State on its home turf and got steamrolled in Denver.

Boston needs only a couple wins over its final four games to clinch that No. 2 spot. Elias Sports Bureau notes that, over the last 14 seasons, the No. 1 seed in the East has reached the Finals only three times, while the No. 2 seed has played in the title round eight times. Alas, it's worth pointing out that five of those instances of the No. 2 seed making the Finals were teams featuring James (Heat three times; Cavs twice).

The Celtics will be heavy favorites in the opening round of the postseason against whomever they draw, regardless of final position. BPI projections suggest they should be rooting to line up with the Wizards more than the Raptors in Round 2, but Boston is in no position to be choosy at this point.

Wednesday's loss all but ensures that, if Boston is lucky enough to see Cleveland again in the Eastern Conference finals, they will do so on the road. For a Boston team with a bright future, including possibly the best odds of the No. 1 pick in May's draft lottery thanks to the Brooklyn Nets, just getting to the East finals would be a big step in the right direction.

But you can tell these Celtics are eager to make the leap and prove they are closer to a legitimate title contender than most think or more than they've shown to this point.

They'll get another chance in the postseason. They'll have to play more inspired ball than they did Wednesday, especially if they see the Cavaliers again.

"I don’t think [Wednesday's loss] means anything [if the Celtics see the Cavs again]," Al Horford said. "But we can definitely see there are some things we need to work on as a group, and we need to be better."