Young Flavia Pennetta of Italy scored a major upset when she demolished fourth seed Mary Pierce of France in straight sets to storm into the semi-finals of the $140,000 WTA tournament in Hyderabad on Thursday.

The 20-year-old Italian displayed immense mental toughness to shock the Frenchwoman 7-6 (7/4), 6-3 and set up a clash with second seed Tamarine Tanasugarn of Thailand, who got ther better of Maria Kirilenko of Russia 7-6 (8/6), 6-3..

Giant-killer Akiko Morigami of Japan also displayed brilliance before brushing aside Silvija Talaja (Croatia) 6-4, 6-2 to book a berth in the last four stage. She will meet Iroda Tulyanganova of Uzbekistan, who rallied to get the better of  Tzipora Obziler of Israel 4-6, 6-2, 6-0 in another quarter-final.

Pierce said her concentration was disturbed by a sore throat.

"I had throat infection and it was bothering a bit. Though I tried to play good shots I really couldn't," Pierce said, adding she hopes to be back in form for the doubles match.

Results

Quarter-finals: Flavia Pennetta (Italy) bt Mary Pierce (France) 7-6 (7/4) 6-3; Akiko Morigami (Japan) bt Silvija Talaja (Croatia) 6-4, 6-2; Iroda Tulyanganova (Uzbekistan) bt Tzipora Obziler (Israel) 4-6, 6-2, 6-0; Tamarine Tanasugarn (Thailand) bt Maria Kirilenko (Russia) 7-6 (8/6), 6-3.