The Cleveland Cavaliers looked like they were stronger than anyone thought when they swept the Toronto Raptors in the second round of the NBA playoffs. However, the Cavs that struggled to put away the Indiana Pacers in the first round of the postseason returned for the Eastern Conference Finals against the Boston Celtics. Despite losing Gordon Hayward when the season started and Kyrie Irving [VIDEO] before the playoffs rolled around, the Celtics are in the Eastern Conference Finals and blew out the Cavs in Game 1 of their playoff series, 108-83. What doomed the Cavaliers was LeBron James' playing his worst game of the 2018 NBA playoffs.

LeBron struggles in Game 1 loss

LeBron James has led his Cleveland Cavaliers to wins in the playoffs this postseason.

He has averaged 34.3 points, 9.4 rebounds and 9.0 assists per game against the Indiana Pacers and Toronto Raptors. In the first round against the Boston Celtics, LeBron fell to Earth.

In the Game 1 loss, LeBron scored 15 points with seven rebounds and nine assists. Before this, his lowest playoff scoring output this postseason was 22 points in Game 6 against the Pacers. He also had seven turnovers in the game.

Kevin Love, who struggled throughout the entire Indiana Pacers series finally rebounded against the Toronto Raptors, and he led the Cleveland Cavaliers in scoring in Game 1, with 17 points. However, he was limited to eight rebounds in the game, only two on the offensive side of the board.

The Cavaliers team struggles

In what was a crazy interview on Saturday, power forward Marcus Morris said [VIDEO] he was the best person in the NBA to defend and stop LeBron James outside of Kawhi Leonard. With that said, Morris held his own. He scored 21 points on offense, but he also had nine rebounds in the game for the Boston Celtics.

According to the NBA on ESPN, LeBron James only scored five points, shooting two-for-six, in the 24 plays that Marcus Morris guarded him.

The Cleveland Cavaliers struggled all game to put up shots. LeBron James has shot 55-percent from the field throughout the postseason but only hit 31-percent of his shots against Boston in the loss. As a team, the Cavs just hit 36-percent of their shots from the field and a terrible 15.4-percent from beyond the arc.

To make it worse, while the Cleveland Cavaliers only hit 36-percent of their shots, they just had nine offensive rebounds, meaning they received almost no second chance shots.

On the other hand, the Boston Celtics had an astounding 42 defensive rebounds, with Morris pulling down nine himself.

LeBron James gave complete respect to Marcus Morris after the game. James said that the Boston Celtics had a great game plan for Game 1 and that Morris was the start of that plan. Al Horford agreed with that in his postgame interview where he said that Morris is a "tough player" and "knows how to defend," which caused the Celtics to change things up for this game against the Cleveland Cavaliers.

After the game, LeBron James said that the Cleveland Cavaliers have a lot that they need to do to improve before Game 2. He also said that the Boston Celtics made him "uncomfortable" in this game and he has a lot of film to watch on Monday.

This matched up with what Boston Celtics coach Brad Stevens said, where he said that LeBron James will make his shots. However, he said that the Boston Celtics worked hard "by committee" and they were locked in and will have to do the same on Tuesday if they want to win again.

According to ESPN, the 26-point halftime deficit was the worst ever for a LeBron James playoff team. Boston Celtics rookie Jaylon Tatum, who plays the same position as James, added 16 points. Even Al Horford (20 points) and Jaylon Brown (23 points) scored more than LeBron in the game.

The Eastern Conference Finals are far from over with, and the Cleveland Cavaliers can win if they just hit their shots, but they have to play much better than they did in Game 1 if they want to make it to their fourth straight NBA Finals before LeBron James leaves town again.