Vitalia Diatchenko claimed a shock win over second seed Naomi Broady in the first round of the OEC Taipei WTA Challenger on Monday.
Diatchenko won this tournament two years ago and defied the odds to oust Britan's Broady 6-3 2-6 7-6 (7-4) on the opening day of the 125K Series event.
Ranked 553rd in the world, Diatchenko was not expected to trouble an opponent inside the top 100 but the Russian wildcard - best by injuries in the last two years - broke twice and held her nerve in a decisive tie-break to advance.
Fifth seed Risa Ozaki also made an early exit, losing 6-1 6-3 to outsider Olga Govortsova, on a day in which Dalila Jakupovic and Miyu Kato reached round two.
Third seed Oceane Dodin fought back to avoid an upset and reach the second round of the Engie Open de Limoges at the expense of Alexandra Cadantu.
Dodin, the only seed in action on day one, made hard work of consigning the world number 275 to a 2-6 6-4 6-2 defeat.
Ekaterina Alexandrova and Ivana Jorovic beat Galina Voskoboeva and Fiona Ferro respectively in the other first-round matches.