World No.8 Agnieszka Radwanska of Poland extended the slump of Serbia’s Ana Ivanovic by defeating the former world No.1 7-6(4) 6-4 in the first round of the Porsche Tennis Grand Prix in Stuttgart. Ivanovic’s last match prior to the tournament in Stuttgart had been another loss to Radwanska, in the third round of the Sony Ericsson Open in Miami.

Despite facing disappointment after disappointment the world No.57 Ivanovic is staying positive, or at least she is trying to project such an image:

It was a tough loss but what doesn’t kill you makes you stronger. I have to be positive. I’m trying to make every shot perfect and it’s just not coming every time. I just need to relax more. A few mistakes here and there are costing me matches. I just have to be patient.

The 22-year-old Ivanovic, champion at the clay-court Grand Slam of Roland Garros in 2008, was playing her first match on clay in 11 months at this year's Porsche Tennis Grand Prix.

The fifth-seeded Radwanska will play Shahar Peer of Israel in the second round. (photo: sr_cranks)

Dinara Safina hasn't competed since withdrawing from the fourth round of the Australian Open in January and resumed training only on April 3. The Russian former world No.1 entered the Porsche Tennis Grand Prix in Stuttgart this week, the tournament at which she was runner-up last year, but will have to watch the state of her back closely in order for the potentially career-threatening injury not to reappear.

"Everybody, including my brother Marat (Safin), told me to take my time but it was really difficult because I wanted to come back on court so badly," said the 24-year-old Safina, seeded second at Stuttgart. "Right now I feel safe and comfortable, but I need to watch closely that it stays that way."

Safina is worried that the injury, which started bothering her in late 2009, could have a serious impact on her future: "My back injury is the worst you can get, because if things go wrong again, that might be it for my professional career altogether." (source: Yahoo, photo: Upali Wickramasinghe)

Rumors from this month's Family Circle Cup when Liezel Huber played with Nadia Petrova turned out to be true - Cara Black and Liezel Huber have split up, which ends one of the most legendary doubles teams of the era.

"On a personal note, my regular doubles partner, Cara Black and I are taking a mutual break from being exclusive doubles partners," Huber wrote.

"Both Cara and I are entered in Stuttgart with different partners but we continue to strive to do what we love most and that is to compete on the tennis court. I just wanted to thank everybody for their support. It was not any easy decision but we announced it today. We both want to be better players and right now it is best for us to just take a little break. We might get back together and we might not."

"Do not be surprised to see us playing with each other or with someone else in the next couple of months," Huber said. "It was not an easy decision. We have had a great partnership and we are appreciative of all the fan support."

Black and Huber shared the No.1 doubles ranking for over two years and won 29 titles together, including four Grand Slams and two Sony Ericsson Championships titles.

Black has spent the second most weeks in Tour history as the world's No.1 doubles player, trailing only Martina Navratilova. Huber has spent the third most weeks at No.1.

Cara Black entered the Porsche Tennis Grand Prix with Shahar Peer, while Liezel Huber's partner at the tournament is Jelena Jankovic. (source: On the Baseline, photo via Sony Ericsson WTA Tour)

Svetlana Kuznetsova, who had lost her last six finals, defeated world No.1 Dinara Safina 6-4 6-3 at the Porsche Tennis Grand Prix to win her first title since August 2007.

Kuznetsova was in command in the all-Russian final and sent Safina to a third final defeat of the season, after Sydney and Australian Open. Safina had five break points, but converted none of them, while Kuznetsova the 2004 US Open champion now ranked No. 9, converted two out of four.

Safina was playing her first tournament since becoming No.1. Kuznetsova will definitely remember this victory, it’s her first title in a long time, plus, she won the white Porsche. (photo via Yahoo)

World No.1 and top seed Dinara Safina once again used her impressive comeback skills to defeat Flavia Pennetta 3-6 7-5 6-0 and reach the Stuttgart final where she will face fellow Russian Svetlana Kuznetsova.

The world No.14 Pennetta seemed to be on a good way to victory as she won the first set and was close to winning the second, too. However, when Safina leveled at 5-5 in the second set, she never looked back and won the next eight games. Pennetta showed powerful groundstrokes, but as she lost her chances she became burnt out and Safina started dominating.

Safina now has a 6-0 head-to-head record against Pennetta.

Earlier, fifth seed Svetlana Kuznetsova crushed compatriot and second seed Elena Dementieva 6-4 6-2 with surprising ease in just 67 minutes to book her place in the Porsche Tennis Grand Prix final.

In Sunday’s final Kuznetsova will be trying to win her first tournament since New Haven in 2007. Safina will be going for her first title of the season, after losing in two finals in 2009, in Sydney and at the Australian Open. (photos via Sony Ericsson WTA Tour)