Serena Williams is prepared for some "true clay-court tennis", as her French Open preparation continues at the Internazionali d'Italia.

The world number one was bundled out of the Madrid Open semi-finals by eventual champion Petra Kvitova, but was positive about her form.

Williams is a two-time defending champion at the WTA Premier event in Rome, with her 2015 campaign beginning against Anastasia Pavlyuchenkova on Tuesday.

"I'm feeling really good, I was excited to just do a little bit better than I did last time in Madrid," she said. 

"So, one round better [than 2014] is a step up.

"To be here in Rome is good, I feel like Rome is true clay-court tennis and it's a little bit slower than Madrid and it's a little bit more intense. 

"So I'm kind of interested to see how I'll fare here."

Williams was not the only player to note the surface at the Madrid Open was quick for a clay tournament.

Ahead of the major at Roland Garros starting on May 24, Williams felt was privileged to have the chance at a 20th grand slam title.

"Gosh it feels good, to even have an opportunity to be at number 20," the American said.

"With that being said, we'll see what happens, there's always, hopefully I'll have three more chances to get there and we'll just keep taking it one at a time."