Pattaya, Thailand - Top seed Ana Ivanovic tumbled out off the Pattaya Open on Thursday, losing in the first round to Japan's Ayumi Morita, while defending champion Daniela Hantuchova eased into round two.
Ivanovic, who has struggled to regain the form that saw her crowned world No 1 in 2008, lost in three sets (6-3, 5-7, 6-3) to Morita - ranked 47 places below her.
Their first round game was played over three days due to heavy rain which has dogged play on the hard surface in Pattaya and again made the court unplayable for periods of the morning.
Tournament late-entry Hantuchova survived a second set scare from rank outsider Olga Puchkova and eventually won 6-1, 3-6, 6-0.
In the final first round match, seventh seed Elena Vesnina beat Greek challenger Eleni Daniilidou 6-2, 5-7, 6-2.
They join Russian second seed Maria Kirilenko, Romanian Sorana Cirstea and Japan's Kimiko Date-Krumm in the second round.
Results from the fourth day of the WTA Pattaya Open on Thursday (x denotes seeded player):
Ayumi Morita (JPN) bt Ana Ivanovic (SRB x1) 6-3, 5-7, 6-3
Daniela Hantuchova (SVK x6) bt Olga Puchkova (RUS) 6-1, 3-6, 6-0
Elena Vesnina (RUS x7) bt Eleni Daniilidou (GRE) 6-2, 5-7, 6-2
Ayumi Morita (JPN) bt Kimiko Date Krumm (JPN) 4-6, 6-4, 6-1
Nina Bratchikova (RUS) bt Daniela Hantuchova (SVK x6) 6-2, 3-0 - retired
Marina Erakovic (NZL) bt Varatchaya Wongteanchai (THA) 6-3, 7-6 (7/4)
Sabine Lisicki (GER x5) bt Alexandra Panova (RUS) 7-5, 6-2
Anastasija Sevastova (LAT) bt Heather Watson (GBR x8) 7-6 (7/4), 4-6, 6-2
Sorana Cirstea (ROM x4) bt Anastasia Rodionova (AUS) 6-0, 7-6 (7/3)
Elena Vesnina (RUS x7) bt Mathilde Johansson (FRA) 6-2, 3-6, 6-1
Maria Kirilenko (RUS x2) bt Luksika Kumkhum (THA) 5-7, 6-2, 6-2