The Toronto Raptors and Boston Celtics are set to begin their second-round series now that the NBA decided to resume the season. This is the first-ever playoff matchup between the two teams. Both teams are entering the Eastern Conference Semifinals after sweeping their first-round opponents.

The Celtics won the season series three games to one, including a 122-100 win over the Raptors during the NBA restart. In fact, the Raptors' only loss since the NBA restart was that game to Boston.

Both of these teams are playing well, so expect a hard-fought series that will most likely go the full seven games. However, it's the defending champions that will come out on top.

Here are three reasons why the Raptors will prevail in their second-round series against Boston.

Toronto's length

The Celtics' biggest weakness is their lack of size. With Daniel Theis and Enes Kanter as their main men in the middle, the Celtics don't have elite rim protection. On the flip side, one of the biggest strengths for the Raptors is their length. That length has allowed the Raptors to be one of the best defensive teams all season.

Unlike the Celtics, Toronto has great rim protection. Former Defensive Player of the Year Marc Gasol and Serge Ibaka control the paint defensively. Not to mention, Kyle Lowry (assuming he's healthy and able to play) steals possession by the charges he takes every game.

Raptors, Pascal Siakam, Marc Gasol, Spurs

Everyone within Toronto's rotation contributes defensively. Fred VanVleet leads the team with 1.9 steals per game. Pascal Siakam, OG Anunoby and Norman Powell are versatile defenders who can guard multiple positions.

Toronto ranked second in both points in the paints allowed and defensive rating during the regular season. Their defense hasn't fallen off in the playoffs, as they're second in blocks per game and opponent points off turnovers.

Offensively speaking, expect Toronto's length to help its frontcourt players have big games during the series. See how Joel Embiid averaged 30 points and 12 rebounds per game in the first round against Boston. The Raptors should attack the Celtics inside and take advantage of this.

Balanced scoring

One thing that is so impressive about the Raptors is how balanced offensively they are. Toronto is not reliant on one player to carry the offensive load. Instead, they have multiple players who are able score over 20 points any given game.

During the sweep of the Nets, the Raptors had three different leadings scorers. VanVleet led the Raptors in scoring during Games 1 and 2. Siakam led Game 3 with 26 points, while Powell closed out the series leading the Raptors with 29 points in Game 4. In addition, Ibaka scored 27 points in Game 4.

Fred-VanVleet-Raptors

Aside from multiple 20-point scorers, the Raptors also have a bench that can take over games. During the playoffs, Toronto leads the NBA with 56.5 bench points per game. In Game 4's 150-point explosion, the Raptors' bench broke an NBA playoff record by scoring 100 of those points.

The Celtics have a trio of excellent scorers in Jayson Tatum, Kemba Walker and Jaylen Brown, but the loss of Gordon Hayward hurts and the bench isn't all that deep.

Championship pedigree

When Kawhi Leonard left Toronto this offseason, many thought the Raptors' championship window had closed. However, the Raptors have excelled this season with their newfound championship pedigree. During the regular season, Toronto ranked third in win percentage in clutch games. When games get close and execution is needed the most, Toronto is consistently able to dig down and make plays when it matters.

Raptors-Kyle-Lowry-Nick-Nurse

On top of championship pedigree, the Raptors have arguably the best coach in the NBA. Nick Nurse was just named Coach of the Year. Brad Stevens is a terrific coach in his own right, but he has never been in the NBA Finals.

For all these reasons, the Raptors will win a physical and chippy series against the Celtics in seven games and advance to the Eastern Conference Finals for the second straight season.