Angelique Kerber was the biggest seed to fall at the Qatar Total Open in Doha Tuesday as the world number six lost in straight sets to one of the WTA Tour's fastest rising stars.
Mona Barthel of Germany sent her compatriot home from the $2.369 million tournament with a 6-1, 6-2 thrashing that included four aces from tall 22-year old and a barrage of flat, powerful groundstrokes that kept the more experienced German pinned to the baseline.
Barthel, who collected her 14th win of the season, will face the winner of Romanian Sorana Cristea, who advances after coming back from a set down to beat Ons Jabeur of Tunisia 2-6, 6-3, 6-0, and former world number one Caroline Wozniacki.
The upset was the biggest surprise of the 19-match day that included easy wins for second seed and world number two Serena Williams, who needed less than an hour to put away her fellow training partner Daria Gavrilova 6-2, 6-1.
"Mostly I've just been trying to play smoothly and avoid problems, and just do the things I've been working on," she said. "Physically I'm feeling better, and hopefully I can stay on that level. Let's go onto the next round now."
She'll face the winner of Italy's Roberta Vinci, who beat a retiring Yanina Wickmayer of Belgium 6-2, 2-1 and Poland's Urszula Radwanska, younger sister to Agnieszka, who demolished Nadiya Kickenok of the Ukraine 6-1, 6-0.
Third seed Maria Sharapova also breezed through her opening round match against France's Caroline Garica, stroking five aces in a 6-3, 6-2 victory.
"I was quite happy with the way I played because my opponent had played a few matches already, so she's been able to get into that match atmosphere," said Sharapova. "Sometimes that's a benefit. I wanted to start really strong. I had a really tough match against her in our previous encounter, so I really wanted to start better this time, as opposed to the way I started against her last time."
Her win sets up the possibility of a fascinating draw against up-and-coming teenage Sloane Stephens after the American had little trouble with Georgia's Anna Tatishvili.
The surprise Australian Open semi-finalist will first have to find a way past veteran Klara Zakopalova of the Czech Republic.
France's Marion Bartoli almost joined Kerber on the casualty list as the French number one struggled in her opening set against Italy's Francesca Schiavone, falling to a quick 1-4 deficit and looking at times lost without the visual support of her father and former coach, Dr. Walter Bartoli.
However, a quick regroup allowed the world number 10 to break back on the former French Open champion and take the opening set to a tie-break, which Bartoli duly won 7-6(5) before easing away to a 6-3 victory in the second.
The odd scheduling of the WTA Premier event - which has seen several players play back-to-back first and second round matches while and entire portion of the draw, including top seed Victoria Azarenka, has yet to hit a ball in anger - continues Wednesday with debuts from Italy's Sara Errani, Radwanska, Sam Stosur of Australia and 2011 Wimbledon champion Petra Kvitova.