The Miami Heat have thoroughly outplayed the Celtics, the same team that defeated the Sixers in seven games and triggered Doc Rivers’ firing. The Sixers were dangerous when they put it all together. But James Harden couldn’t do that consistently. He had a couple of good games in the NBA playoffs and that was it. Joel Embiid couldn’t remain healthy or come up big in the games when the Sixers needed him the most. That’s obvious while watching the Eastern Conference finals. The Miami Heat have a chance to pull off a gentleman’s sweep of the Boston Celtics. Miami takes a 3-1 series lead into Thursday’s Game 5 at TD Garden. » READ MORE: The Sixers still have options in their coaching search, but Nick Nurse should top their list This is the same Celtics team that defeated the Sixers in seven games in the conference semifinals, leading to coach Doc Rivers’ firing. At that time, the belief was that the winner of that series would win the NBA title. But, aside from their Game 4 victory, the Celtics have been thoroughly outplayed by the Heat. All-NBA selections Jayson Tatum and Jaylen Brown have struggled. Boston has had no answers for Heat forward Jimmy Butler. And folks are questioning whether the Celtics should part ways with first-year coach Joe Mazzulla. This comes after Mazzulla’s adjustment to insert Robert Williams III in the starting lineup alongside Al Horford had a negative impact on the Sixers in Games 6 and 7 of the conference semifinals. It comes after Tatum scored a Game 7 record 51 points to eliminate the Sixers. And it comes after the Celtics defenders, combined with the Sixers’ lack of creativity, limited Embiid and Harden to combined 8-for-29 shooting in Game 7. There was a lot of optimism surrounding the Embiid-Harden pairing in the regular season. And with just cause. Embiid won his second consecutive scoring title (33.1 points per game) while being voted league MVP. Harden was the NBA’s assists leader (10.7). And with the duo leading the way, the Sixers were the league’s hottest team from early December through March. The problem is, attention to detail and competitiveness reaches a different level in the postseason. Not only are the teams better, but they have more time to game-plan. And the conference semifinals revealed that Embiid and Harden will have postseason struggles moving forward. At 33, Harden is getting older. He wants to be in a system that will allow him more freedom with the ball. This season, his primary job was facilitating. That said, if the Sixers lose Harden in free agency, they could have trouble replacing him. But if he stays, they can’t win with him. » READ MORE: Frank Vogel interviews for Sixers’ head coaching job and emerges as top candidate Harden did have an epic performance in Game 1 of the semifinals with Embiid sidelined with a sprained right knee ligament. He had a game-high 45 points, tying a career playoff high in the 119-115 victory. Fifteen of his points came in the fourth quarter, including the go-ahead basket with 8.4 seconds left. In Game 4, Harden had game highs of 42 points, nine assists, and four steals in the 116-115 victory. His wide-open, 24-foot three-pointer in front of the Sixers bench with 19 seconds left was the game-winner to cap his best home game as a Sixer. As good as he was in those games, the Celtics broke down on both game-winning shots. And he struggled mightily in Games 6 and 7 after Boston made the proper adjustments. Harden had 13 points on 4-for-16 shooting in the 95-86 Game 6 loss. He followed that with nine points on 3-for-11 shooting along with five turnovers in the 112-88 Game 7 defeat. And Harden failed to score in the fourth quarters of Games 5, 6, and 7 on a combined 0-for-6 shooting. That’s why the Sixers’ best bet would be to let Harden walk if he opts out of his $35.6 million deal and becomes a free agent. Again, if that happens, they won’t be able to replace him adequately in free agency because of the salary-cap space projected to be available to the Sixers. In addition, the Sixers really don’t have any tradable assets to bring in a suitable replacement to pair with Embiid. Meanwhile, Embiid also came up small in the biggest game of the season. He looked disinterested while settling for perimeter jumpers and scoring 15 points on 5-for-18 shooting in the Game 7 loss. » READ MORE: Former Sixers coach Doc Rivers is set to interview for Phoenix Suns job The loss dropped him to 0-3 in Game 7s and 0-5 in second-round series. For now, Embiid is viewed as an often-injured player who performs in the regular season but can’t win the big game in the postseason. While playoff series are about matchups, watching the Celtics struggle reveals just how far away the Sixers are from winning an NBA title.