Roddick, seeking his first tournament victory in 2009, needed just 61 minutes to polish off Ginepri, drilling 11 aces and hitting 79 percent of his first serves.
"I?m in a pretty good groove serving right now, and feel like a lot of the work I put in during December is showing itself,'' Roddick said.
In the Cellular South Cup women's event, top-seeded Caroline Wozniacki rallied past Michaella Krajicek 2-6, 6-3, 6-3 to reach the semifinals.
Lleyton Hewitt and Christophe Rochus advanced to the men's quarterfinals.
Hewitt, once the top-ranked player in the world, took another step back from major hip surgery last August, defeating Chris Guccione, 6-2, 7-6 (4). Rochus, a 30-year-old who spent much of 2008 on the Challenger circuit to rebuild his rating, beat No. 7 seed Mardy Fish 6-2, 6-4.
Top seeds Andy Roddick and Caroline Wozniacki played later Thursday night.
The 27-year-old Hewitt, who reached a quarterfinal earlier this year in Sydney, has already knocked off two big names this week. He ousted third-seed James Blake in three sets late Wednesday and in an exhibition on Monday beat Hall-of-Famer Pete Sampras.
"I'm feeling pretty good about the way things are going. Jim and I did a lot moving in that three-set match and I was happy with the result. Today against Guccione, there weren't so many long points, and that was probably good.''
Hewitt gave up only eight points on serve in the match and had 10 aces.
"The thing for me right now is getting used to match conditions again, playing a lot of guys, going through a lot of big points,'' he said. "No matter how good you feel on the practice court, you have to keep playing matches to get sharp. That's what I'm working on now.''
It was only the second time Hewitt had faced Guccione, a teammate on the Australian Olympic and Davis Cup teams.
"We practice together, gone to battle for our country together. We know everything about each other's games, so it's tough to go through something like this,'' Hewitt said.
Rochus put together a 41-15 record with two titles and five finals on the Challenger Tour.
"When your ranking drops like mine did, you have a choice: Retire or fight,'' Rochus said. "So I went to the Challengers Tour, where you play a lot of matches for no money against players as good as they are at this level. Winning there got my confidence back.''
He overcame 14 aces by Fish, who only put 45 percent of his first serves in play.
"If Mardy plays well, I lose 6-3, 6-4. That's how it is. But if he plays bad, that gives me an opening,'' Rochus said.
No. 2 seed Juan Martin Del Potro cruised in the quarters with a 6-3, 6-4 win over Ernests Gulbis. No. 5 Radek Stepanek beat Stefan Koubek 6-2, 6-4, Igor Kunitsyn rallied past Philipp Petzschner 3-6, 6-4, 6-4, and qualifier Dudi Sela won 7-6 (4), 7-6 (4) over Florent Serra, who had beaten Robin Soderling in round one.
In the women's draw, third-seeded Lucie Safarova was eliminated in the quarterfinals by Sabine Lisicki of Germany 6-3, 6-4. Anne Keothavong survived a 6-2, 1-6, 6-2 match with fifth seed Marina Erakovic. Victoria Azarenka of Belarus advanced to the semifinals with a 6-4, 6-2 win over Pauline Parmentier.
Stepanek advances to quarterfinals at SAP Open
Roddick breezes intoВ Memphis quarters
Marcelo Delighted With First Real Madrid Goal
