ATLANTA (REUTERS) - Lou Williams contributed 21 points and eight assists while starting in place of injured star Trae Young to help the Atlanta Hawks post a 110-88 victory over the Milwaukee Bucks on Tuesday (June 29) and tie the National Basketball Association Eastern Conference Finals at two games apiece.

Bogdan Bogdanovic made six three-pointers while adding 20 points for the fifth-seeded Hawks, who never trailed and led by as many as 25 points.

While Young sat out Game 4 with a bone bruise in his right foot, the third-seeded Bucks lost their own star when two-time NBA Most Valuable Player Giannis Antetokounmpo hyperextended his left knee in the third quarter and did not return.

He had 14 points and eight rebounds in 24 minutes before exiting with 7min 14sec left in the third period.

Game 5 is on Thursday night in Milwaukee.

Clint Capela added 15 points for the Hawks before leaving with 3:28 left in the fourth after taking an elbow to his nose from Milwaukee's Sam Merrill.

Kevin Huerter also scored 15 points for Atlanta.

Jrue Holiday recorded 19 points and nine assists and Khris Middleton had 16 points and eight rebounds for the Bucks, who were a woeful eight of 39 (20.5 per cent) from three-point range while shooting 39.3 per cent overall.

Antetokounmpo was helped off the floor by his brother Thanasis after getting hurt.

He got injured when he leapt to defend an alley-oop pass to Capela. Antetokounmpo hyperextended his knee as he landed. He fell to the court in intense pain, grabbing the knee, and Capela fell on top of him after scoring the basket.

Young was injured in Game 3 on Sunday night when he inadvertently stepped on an official's foot.

Cam Reddish added 12 points and Danilo Gallinari tallied 10 for Atlanta, who shot 50 per cent from the field and were 13 of 38 (34.2 per cent) from behind the arc.

Capela's basket on the play in which Antetokounmpo was hurt ignited a 17-2 burst that saw the Hawks open up a 77-54 lead with 3:18 left in the third.

Bogdanovic knocked down three three-pointers during the run.

Reddish's three-pointer with 29.7 seconds left elevated Atlanta's lead to 87-62 entering the fourth quarter.

Reddish and Huerter buried baskets 13 seconds apart in the final stanza to make it 104-80 with 4:20 left, prompting Milwaukee coach Mike Budenholzer to pull Holiday and Middleton and look toward Game 5.

Williams hit all four of his first-half field-goal attempts - including one three-pointer - while scoring 13 points to help the Hawks hold a 51-38 half-time lead.