Dwyane Wade and LeBron James shared the podium after dropping Game 3 of the Eastern Conference Finals to the Boston Celtics, 101-91. Together they laughed when Wade discussed his failure to earn a single free throw attempt. With a chuckle, James mentioned the time earlier this season when he failed to register a single assist. The duo appeared to shrug off the blowout loss like it was a pickup game in the middle of August.

Two days later neither Wade nor James reached the podium after dropping Game 4 in overtime, 93-91. The Heat sent Mario Chalmers instead, a laughable notion considering how little the point guard, who scored 12 points on 13 shots during the game, means to his team’s success relative to his two superstar teammates. The reporters at the press conference asked Chalmers a few questions, but their general reaction to his appointment as Miami’s spokesman was one of confusion. Wade and James did not duck the media, but they answered questions from the locker room. And this time, they didn’t do so much laughing.

The Eastern Conference Finals has become a legitimate series, maybe even a bar fight, and the Miami Heat know it.

The Celtics took both games on their home court. They were alternately brilliant and underwhelming, morphing from offensive juggernaut to stalled 1993 Toyota Corrola during one halftime intermission, but they won twice. They’ve sent the series back to Miami knotted at 2-2, and they’ve Inception’d the Heat with the thought that perhaps a return trip to the NBA Finals isn’t predestined.

“No one said this was going to be easy, and that’s what we talked about in the locker room,” coach Erik Spoelstra said in the moments after Game 4. But the juxtaposition of the Heat’s laughs after Game 3 and their apparent concern two days later, hinted that maybe Spoelstra’s players initially felt differently than he did.

Regardless of how much competition the Heat felt the Celtics would provide, we’ve arrived at the ever-crucial Game 5.

“We have to win here. Every Game 5 is a Game 7 as far as I’m concerned,” Doc Rivers told reporters at the Celtics’ shootaround Tuesday.

The Celtics have done well in Game 5s. Perfect, even, at least on occasions when the series is tied at 2-2. The Big Three-era Celtics are 8-0 in Game 5s of a tied series. Seven of those came at the TD Garden. The lone road win came against James in the 2010 Eastern Conference semifinals. It was the last game James played in front of a home crowd in Cleveland. It was also, at least until his production oddly tailed off in the later stages of the 2011 Finals, his career’s biggest bruise.

The Heat are expected to get a boost tonight from Chris Bosh’s return. Though Rivers said the Celtics would not change either their offensive or defensive strategy because of Bosh, the reality is that Bosh’s mere presence changes things. He is a seven-time All-Star, after all, and the NBA’s highest-percentage shooter this season from 10-15 feet away from the hoop.

Beckley Mason wrote a nice piece for TrueHoop on the Bosh Effect. The gist of his work is that Kevin Garnett has been able to roam off his primary assignment like a free safety, often abandoning his own man in favor of providing help for his teammates.

Garnett’s stellar smarts on defense even allow him to snuff out most of the plays designed to feed Wade by proactively rotating to prevent Wade from even attempting a drive.

Wonder why Mario Chalmers is having such a great series? It’s in part because Garnett is so focused on Wade that he’s out of place to protect the rim when Chalmers attacks off the dribble. The video suggests the Celtics have simply decided to concede some of those plays to stop Wade.

Yet it’s not like Wade can’t score against the Celtics. Keep in mind that he put up over 30 points per game on 51.5 percent shooting against Boston in the playoffs just a year ago.

What was different then? The Heat had Chris Bosh.

Heat Index’s Tom Haberstroh explains how much Bosh’s presence has meant to Wade this postseason:

Looking at his numbers in NBA.com’s stats tool, we find that 56 percent of Wade’s shots come inside the paint when Bosh is on the floor in the playoffs, and he’s making those shots at a scorching 76 percent clip. When Bosh has sat, those numbers tumble; only 51 percent of his shots come in the paint, and his conversion rate plummets to 61 percent.

Garnett has been free to provide as much help on Wade and James as he wants because none of Miami’s healthy big men are worthy of defensive attention. Bosh, even if hindered by his lower-abdominal strain, is worthy. Boston’s response to dealing with Wade/Lebron while simultaneously dealing with a capable big man is just one of the several questions which will frame Game 5.

We didn’t always know how much it would, but Game 5 matters. Quite a bit. Even the Heat know that now.