Widom won 3-6, 7-6 (2), 6-4 for his first victory in an ATP event since he won a first-round match at Delray Beach in January 2006. The 25-year-old Widom, ranked 270th, has battled through two bouts of eye cancer, two knee surgeries and an elbow injury since 2006.
"It feels really good,'' Widom said. "This was a step in the right direction. I played the big points and tried to take the match to him and succeeded. This last year, I thought my career was over because of the various injuries I had suffered.''
The 44th-ranked Ginepri is 1-4 on the tour this year and hasn't won a match since Auckland Open in early January.
Widom will play Taylor Dent in the second round on Thursday.
In other first-round action, Denis Gremelmayr needed three sets to beat Roko Karanusic, 3-6, 7-6 (4), 6-2; Chris Guccione beat Guillermo Canas, 7-6 (7), 7-5 and Ernests Gulbis defeated Ricardo Mello 7-6 (4), 6-4.
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