Safin finished strong in a 6-2, 3-6, 6-1 win over Petzschner. He didn't face a break point in the first or third sets and won 60 percent of the points in the decisive set.
No. 6-seeded Jurgen Melzer zipped by Marcos Daniel 6-3, 6-2 in 55 minutes but Evgeny Korolev knocked off seventh-seeded Fabrice Santoro 4-6, 7-6 (7-4), 7-6 (9-7). Santoro twice had Korolev at match point but failed to finish him off.
Robby Ginepri defeated local favorite Danai Udomchoke 6-4, 6-3 while others advancing from the first round with wins Tuesday were Marsel Ilhan, Andreas Beck and Ernests Gulbis.
No. 3-seeded Sam Querrey withdrew after he cut his right forearm when he fell through a glass-topped table as he put on his shoes. Querrey had emergency surgery and will miss 4-6 weeks of competition but is expected to fully recover.