Home favourite Nigina Abduraimova provided a first-round shock at the Tashkent Open as she knocked out fourth seed Lara Arruabarrena.
The world number 189 has struggled to make an impact on the WTA circuit this season but produced a stirring display in her home tournament to win 7-5 6-4.
Abduraimova converted each of the break-point opportunities that came her way in the first set to claim an early lead, and completed victory with another break of Arruabarrena's serve.
There were fewer problems for a number of the other seeds in action as Irina-Camelia Begu, Karin Knapp, Donna Vekic and Misaki Doi all won in straight sets.
Second seed Begu, who won this WTA International hard-court event in 2012, only needed 67 minutes to record a 6-3 6-1 triumph over Kateryna Kozlova.
Having broken her Ukrainian opponent in the first game, Begu went on to win seven consecutive games to take the first set and establish a healthy lead in the second.
Knapp was a 6-2 7-6 (7-3) winner over Cagla Buyukakcay, while Vekic looked set for a battle with Mandy Minella after a close opening set but then won all six games in the second to progress 7-5 6-0.
Doi set up a second-round match with Olga Govortsova, the beaten finalist in 2013, courtesy of a 6-4 6-3 win over Katerina Siniakova. Govortsova beat Margarita Gasparyan 6-3 6-4.
Former winner Ksenia Pervak booked her place in the second round with a straight-sets win over seventh seed Anna-Lena Friedsam, but 2009 champion Shahar Peer was beaten 6-3 7-5 by Jelena Ostapenko.
Lesia Tsurenko and Alexandra Panova will also feature in the next round after they completed victories on Tuesday, the former the only player to be taken to three sets.