Johnson, 23, won 6-7 (5-7), 6-4, 7-5 to advance to the third round of the final hard court tune-up for the looming U.S. Open where he will face Yen-Hsu Lu of Taiwan.
The rest of the seeded competitors on Tuesday's card also moved on.
Wild card Mardy Fish of the United States was forced to withdraw due to heat stroke near the end of a hard-fought three-set match against No. 11 seed Jarkko Nieminen of Finland.
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