WATCH: Al Horford's sister provides hilarious reaction to his career night vs Bucks

After posting a career night for Boston in Game 4 of their playoff series, Al Horford‘s sister explained why it happened to the Bucks. His sister, Anna Horford, shared a video clip of her brother taking exception to Giannis Antetokounmpo’s taunting after a dunk early in the third quarter.

Giannis went down the length of the court and finished with a dunk over Horford, then stared him down after the play and received a technical foul for taunting. The video showed Horford’s immediate reaction to the taunting, something that his sister explained is what he looks like when he’s “pissed” at something.

This is where the Bucks f*cked up 😂 I know that look… He was pissed.
pic.twitter.com/rYFn45zb61

— Anna Horford (@AnnaHorford) May 10, 2022

Al Horford’s sister explains his angry face

Heading into Game 4 of their second-round playoff series with Milwaukee, Boston knew they would be without center Robert Williams for the game. As a result, 35-year-old Al Horford stepped up in an incredible way, shooting 11-for-14 from the field and finishing with 30 points, eight rebounds and three assists. The Celtics won on the road, 116-108, and recaptured home court advantage in the now-tied series behind the former Florida Gators‘ star and his career night.

The 35-year-old played 42 minutes with Robert Williams sidelined, and he made them count. Horford went 11-of-14 with 30 points, eight rebounds, and three assists in a 116-108 victory.

According to his sister — and later Horford himself while answering questions after the game — Horford flipped a switch when Antetokounmpo stared him down. Playoff games normally get much more physical the longer a series goes as players battle every night, and the Bucks and Celtics showed just how tense the games can get.

Horford got his revenge not just in the victory, but on a monster dunk over Antetokounmpo’s defense in the fourth quarter to cap off a 10-0 run by Boston. Horford finished the dunk and screamed in celebration, but was assessed a technical foul himself on the play as he brought his elbow down onto Antetokounmpo’s head after the dunk. The play was incidental enough to not warrant any further action by officials, but the direct contact Horford made with his face was enough to draw the technical foul.

Boston now returns to their home court with the series tied at 2-2, seeking to take the lead over the defending NBA champions.