In the first quarter of Tuesday night's game between the Sixers and the Celtics, Boston center Al Horford thought he was playing tough defense on Philadelphia star Joel Embiid.

The referees disagreed, and Horford wasn't happy:

In the clip, Horford appears to have gotten all ball on the block, but was also holding Embiid's back during the shot. His protest of the call earned him a technical foul.

JJ Redick made his one free throw for the technical, and Embiid made one of two shots for the shooting foul.

For the season, Horford is averaging 12.4 points, 6.6 rebounds and 3.9 assists. The 32-year-old is a five-time All-Star. This is his second season in with Boston after signing a four year, $113 million contract with the team prior to the 2016-17 season. The deal includes a player option for next season.

This game is an important one for both teams. The Sixers currently hold the fourth seed in the Eastern Conference, while the Celtics are a game back in the fifth spot. The third seed Indiana Pacers, at 38-19, are also within striking distance of both teams.

According to ESPN's BPI Playoff Odds, both teams have a greater than 99.9% chance of making the playoffs.

However, the system favors Boston, giving them a 6.3% chance of winning the championship, compared to a 1.3% chance for the Sixers.