He did not return to the game, and his status moving forward was not immediately clear.
Giannis' knee bends the wrong way
The two-time NBA MVP sustained the injury in the third quarter after jumping to defend a Hawks alley-oop. When he landed, his left knee buckled backward, and he fell to the floor in pain.
He eventually stood up and walked to the locker room with assistance.
Moments later, he joined his teammates on the Bucks bench, walking with a limp on his own.
His stay on the sideline was brief. He walked back into the tunnel shortly before the Bucks announced the diagnosis of a hyperextension.
Will series shift on Giannis' injury?
The Bucks entered the night with a 2-1 series lead facing a Hawks team missing star guard Trae Young, who suffered a bone bruise on his right foot in Game 3. Atlanta held a 62-52 lead when Antetokounmpo left the game and went on to secure a 110-88 win to tie the series at 2-2.
The series returns to Milwaukee for Game 5 on Thursday. Antetokounmpo's status for that game and beyond are in doubt. He's expected to undergo further testing on his knee on Wednesday, according to ESPN's Malika Andrews.
Bucks head coach Mike Budenholzer declined to speculate on his prognosis after the game, telling reporters "we'll see how he is tomorrow."
Antetokounmpo entered Tuesday's game averaging 29.2 points, 13 rebounds and 5.4 assists in the postseason and is obviously key to Milwaukee's hopes of winning an NBA title.
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