The defending champion made 36 unforced errors and had to come from 4-2 down in the second set to secure her second title of the year.
"I made a lot of errors but I hung in there and was able to come out on top in the end," Davenport said.
"She is a really tricky player to play. I never seem to be able to find my rhythm against her. Today I felt like I threw in a bunch of errors but I had to (go for my shots) because I didn't want her to dictate.
"I got the job done and am really happy to have won."
After being broken in her opening service game, Farina Elia frustrated Davenport on the green clay with some superb retrieving and a deft touch, and had a break point chance to lead 6-5.
But Davenport, who struggled with her timing throughout, saved it with a backhand winner and then broke the Italian in the next game to snatch the set.
The 32-year-old Farina Elia was not discouraged, however, and as the errors continued to flow from Davenport's racket, she surged ahead 4-2 and then served for the set at 5-4.
Again, though, Davenport lifted her game when it mattered, breaking back for 5-5 and holding for 6-5 before moving ahead 40-15
Farina Elia saved one match point with a drop shot and backhand into the open court but Davenport then crunched a forehand winner on the next point to clinch victory.
"I think I played my best game today and I have no regrets," Farina Ellia said.
"I think she came up with some unbelievable shots on the big points. When I had break points she came up with an ace or a winner and there wasn't anything I could do."
Despite the loss, Farina Elia was encouraged by her performance.
"I think I really surprised myself this week. I knew that I had done a lot of physical work to get ready for the clay but to recover the way I did, especially when I played two matches in a day, was really amazing for me," she said.
"It gives me a lot of confidence for the rest of the claycourt tournaments in Europe, especially the big tournaments for me like the Italian Open and French Open."
Davenport joined Martina Navratilova, Chris Evert, Steffi Graf and Gabriela Sabatini as the only three-times winners of the title in the tournament's 26-year history.