Hewitt used three second-set breaks to finish off a 7-6 (8-6), 6-3 decision over Haas. Hewitt has a 7-4 career edge in a series that dates to the quarterfinals of the 2004 U.S. Open.
After a first set in which each player won 50 points and had one break, the second set saw five breaks and Hewitt limiting Haas to just 10 points over four games serving.
Philipp Kohlschreiber got by Albert Montanes 7-5, 1-6, 7-6 (7-4). Montanes managed three breaks but Kohlschreiber didn't allow him a break opportunity in the third set before coming out on top in the tiebreaker.
Fabio Fognini held off Tommy Robredo 7-5, 4-6, 6-3 by getting half of his six breaks on the day in the third set.
Also Monday, Bernard Tomic defeated Zhang Ze 7-6 (7-4), 6-4 and Roberto Bautista Agut was a 6-4, 6-2 winner over Grigor Dimitrov.