Lindsay Davenport could not repeat her stunning third-round form as she lost to Russia's Dinara Safina in the last 16 at the Sony Ericsson Open.

The American, 31, beat world number two Ana Ivanovic on Sunday but found Safina too tough, going down 6-3 6-4.

Justine Henin, Svetlana Kuznetsova, Jelena Jankovic, Venus and Serena Williams all made the quarter-finals.

Roger Federer reached the last 16 after Robin Soderling retired trailing 6-3 3-0, but Jo-Wilfried Tsonga went out.

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The 12th seed and Australian Open runner-up lost 6-3 6-3 to fellow Frenchman Julien Benneteau.

Federer was satisfied at reaching the last 16, where he will face Argentina's Jose Acasuso.

"You're sort of happy you got through to the next round," said the Swiss.

"You're not happy for your opponent, because it's never a way you want to win a match, but you've got to push him to give up."

Also through to the last 16 is sixth seed Andy Roddick, who beat Ivo Minar 7-6 6-4.

Elsewhere, fourth seed Nikolay Davydenko of Russia beat Italian Simone Bolelli 6-7 (5-7) 7-5 6-1.

Davenport simply could not find the form that did for Ivanovic on Sunday, making 34 unforced errors, including six double faults, and 20 winners.

"She did everything better than I did," admitted Davenport. "I came up against a player today that was real intense and real eager to win.

"That's the thing with tennis, every day you start over, but hopefully more positives than negatives come from this tournament."