Simon battled for nearly 3 hours before claiming a 4-6, 7-6 (7-5), 6-1 decision over Carlos Berlocq. Simon faced 14 break points -- saving 10 -- overall but none in the third set.
In the third set he recorded half of his six breaks on the day, which allowed him to overcome a service game in which he was good on just 56 percent of his first serves.
Four of the five matches on Monday's schedule went three sets with Robin Haase's 6-4, 6-2 win over Matthias Bachinger in 64 minutes the exception. Haase lost just 10 points over nine service games.
Nikolay Davydenko capped the day's play with a 5-7, 6-4, 6-0 win over Jarkko Nieminen. Davydenko lost 12 points -- one on serve -- in the third set.
LGBT community has 'bullied the American people': Bachmann
Duggar sisters unveil Christian dating rules in new book