German Haas overcome the challenge of his fellow countryman and defending champion Philipp Kohlschreiber 6-3 7-6, which in turn has seen him rise to 13 in the world rankings.
Meanwhile, Switzerland's Wawrinka saw off David Ferrer 6-1 6-4.
"It was the perfect match for me," said Wawrinka. "It's so tough to play David, he's a big champion."
The two winners are now expected to compete at next week's Madrid Masters.