The Hawks have passed a series of increasingly difficult tests following the loss of Al Horford. A bigger challenge is now before them. In a battle of division leaders, the Hawks (11-4) travel to Philadelphia (10-4) for a game Friday night. It's a game that will challenge the Hawks, especially without the scoring, rebounding and defense of Horford. The 76ers rank third in the NBA in scoring average (101.0), second in points allowed (87.4) and first in point differential (plus-13.6). The game also is on the road, where three of the Hawks' four losses have come.