Heading into this compressed season, a matchup between the Miami Heat and Chicago Bulls in the Eastern Conference finals seemed like a foregone conclusion, an inevitable clash of two powerful titans. But ever since the Bulls’ season ended in devastating fashion – with tough breaks and unfortunate health playing a major role – most observers shifted their focus to the Boston Celtics as Miami’s biggest rival in the East.

“Obviously, with the Chicago Bulls being out, this is the biggest matchup the Eastern Conference can have,” Dwyane Wade told reporters on Sunday.

Indeed, the Heat and Celtics face off in the Eastern Conference finals after Miami needed 11 contests to get past the New York Knicks and Indiana Pacers while Boston eliminated the Atlanta Hawks and Philadelphia 76ers in a pair of seven-game series.

Here are five aspects to watch for in this series:

1. The Big Ticket’s delivery: Kevin Garnett had always cringed when a pundit identified him as a seven-foot center. And yet, Doc Rivers’ decision to move the big man to the five spot completely altered the direction of these Celtics. They have lost a plethora of frontcourt pieces over the past year, from Shaquille O’Neal to retirement, Jeff Green and Chris Wilcox to heart issues that, fortunately, were immediately dealt with and Jermaine O’Neal to constant injuries. As the Celtics struggled earlier in the season, Rivers made a move that, in many ways, saved his club’s campaign: He placed Garnett at center to utilize his uncanny skills and relentless nature, to combat the team’s lack of front-line bodies.

Through it all, Rivers had the end-game in mind, a playoff date with the Heat. He knew teams across the East, besides the Bulls, had their own size problems – and he was right. Garnett has performed magnificently in this postseason, carrying the Celtics at times, and has put up averages (19.2 points, 10.8 rebounds) on par with his 2008 championship run per-game numbers (20.4 points, 10.5 rebounds). However, the Celtics will need much more over the course of this series, especially since Chris Bosh is still a ways away from returning due to an abdominal strain. In last season’s East semifinals, it was Bosh who thoroughly outplayed Garnett. Now, Garnett cannot afford to have a double-digit effort – which he has done once during these playoffs – and one would have to wonder whether the Celtics can beat the Heat even if Garnett maintains his playoff averages. He has to go above and beyond against whomever the Heat throw at him; it could very well take 30 points and 10 boards per game out of him to topple the Heat. Now that Bosh is sidelined, the pressure is on Garnett to produce, to deliver a vintage showing that seemed so improbable months ago, but so possible at this point in late May.

2. The feverish pace of James and Wade: For as unforeseen injuries have been throughout the season, LeBron James and Wade put together an unbelievable three-game stretch to close out the Pacers. After the Heat fell behind 2-1, Wade and James combined for 197 points in Games 4-6. Out of nowhere, Miami’s stars seamlessly clicked better than ever in Heat uniforms, a dominant resurgence. They ran the pick-and-roll together to create mismatches, they ferociously drove the ball to the rim, and they took turns shattering the Pacers’ will the way Pat Riley envisioned when he turned the tandem into teammates. Now, James and Wade will face a new test. Frank Vogel’s Pacers challenged the Heat physically; it was the smash-mouth style the coach had to repeatedly preach to not only send a message to Miami, but also his own team. For the Celtics, there is no culture shock entering this series versus the Heat. Boston is a veteran-laden bunch that understands the rigors of defending the freight train that is James and the speed and power mix that is Wade. For as much flack as James and Wade receive at times, they formed true greatness as the series against Indiana wore on. Erik Spoelstra recently told the media in Miami that his two cornerstones must continue their incredible pace. But is that even possible? Will James and Wade have enough in the tank to combine for around 70 points throughout this series?

3. Will Rondo keep his foot on the gas pedal?: The Celtics’ margin for error is already slim, and they can ill afford to have the mind of Rajon Rondo wandering elsewhere. By their own admission, Celtics coaches and players know Rondo is the engine that makes them all go, the quarterback who must maintain his composure and stay engaged from the outset of the series. The formula to beat the Heat over the past two years has been to expose them at two critical positions, point guard and center. Garnett must deliver in a big way, but it is Rondo who has the game-changing ability slowly deteriorating out of Boston’s original big three of Garnett, Paul Pierce and Ray Allen.

As long as Rondo’s head is in the game – which didn’t seem to be the case in Boston’s Game 6 loss to the Sixers when he had just nine points on 4-of-14 shooting – the 26-year-old should have a field day against Mario Chalmers and Norris Cole. Although, in recent tilts between the two teams, the Heat have been willing put James on Rondo for long stretches. Nevertheless, Rondo’s aggressiveness has to be at its all-time high if the Celtics have any chance of pulling off the upset. Much has been made about the fact that Rondo has not forgotten about the injury he suffered against Miami in last year’s postseason, and now he must back up his desire of redemption by tirelessly attacking the Heat. He has to wear Miami down at a position that has long been vulnerable.

4. The health of Pierce and Allen; Bosh’s potential return: Both Pierce and Allen have been hobbled during the Celtics’ run, with nagging lower-body injuries that always seem to hamper players who are in the late stages of their career. With defensive-minded guard Avery Bradley already out with a shoulder injury, Allen is bothered by an ankle ailment that has affected the essence of his game – jump-shooting. He knocked down a pair of crucial three-pointers in the Celtics’ Game 7 win Saturday, but the strain he places on the ankle will undoubtedly elevate while defending Wade as opposed to Evan Turner, Jodie Meeks or Lou Williams. Pierce will also face his toughest challenge to date, in James, and he struggled defensively at times in the last round, especially in Game 7 when he fouled out with over four minutes left.

At least Pierce and Allen are able to play, Bosh would probably say. Bosh missed the final five games of the Heat’s series against the Pacers and remains out indefinitely. He sustained the abdominal strain on May 13, and NBA players tend to miss four to six weeks with the injury. A four-week comeback would have him return on June 10, but by then this conference finals matchup will be over. All the Heat can do now is pray for a speedy recovery, which does not seem likely – although Bosh reportedly did some light on-court workouts Sunday. The Celtics took advantage of injury woes on their side of the East bracket, with Derrick Rose suffering a season-ending torn ACL, and they will look to capitalize one more time, as the Heat’s already-slim frontcourt is primed to be without Bosh for the remainder of the East playoffs.

5. Battle of supporting casts: In a series packed with All-Stars and Hall of Famers, the onus will also fall on the supporting players. At this point every year, an unsung hero or two emerges onto the scene. Both squads are banged up, battered and bruised. Stars are expected to perform true to form on this stage, but it will be up to guys such as Brandon Bass, Shane Battier, Mickael Pietrus and Chalmers to confidently drain shots in clutch junctures of the game. There are also role players like Joel Anthony and Greg Stiemsma – big men asked to snatch critical rebounds and provide rim-protection.

In the Celtics’ 2008 title season, it was the Eddie Houses, the P.J. Browns of the world. For the Heat’s 2006 championship campaign, it was battle-tested veterans Gary Payton and Antoine Walker who knocked down huge jumpers in fulfilling moments. Who will seize the moment this time around?

Prediction: Heat in 7.

The bottom line: The Celtics’ run this season has been so pure and indicative of how special it is when a team on its last stand is fully committed to ending in grand fashion. Rivers’ crew has a sense of urgency and desperation, and they have positioned themselves exactly the way they could have scripted back in December – in the Eastern Conference finals, four games away from this core’s third Finals appearance. The Celtics even took the season series, 3-1, winning the final three games. Still, the Heat are at the top of their game right now, starting with James and Wade, and they have the blueprint to beat Boston in the playoffs after doing so a season ago Ultimately, there are too many if’s, too many must’s, for the Celtics to advance. Yet, they are right where they wanted to be and will give the Heat the fight of their life on what is likely the final ride of this Boston core as currently constructed.