Brisbane - The Brisbane International lost two of its top seeds on Sunday when Germany's Andrea Petkovic and Jelena Jankovic of Serbia both crashed out of the season-opening tournament.
Former champion Kaia Kanepi of Estonia downed fifth seed Petkovic in three tense sets 6-4, 5-7, 6-4. In the first match of the tournament, Croatian wildcard Ajla Tomljanovic sent the sixth-seeded Jankovic packing 7-6 (8-6), 6-0.
The tall and powerful Kanepi, who won in Brisbane in 2012, survived an attack of nerves when serving for the match at 5-2 in the third set to overcome Petkovic in two hours, 26 minutes at the Pat Rafter Arena.
Petkovic, the world number 13, struggled to find any rhythm in the opening set but fought hard in the second to take the match into a decider.
However, Kanepi stepped up a notch in the third to gain two vital breaks and open up a 5-2 lead.
Petkovic fought back to break Kanepi, then held her own serve to get to 5-4, only for the Estonian to hold her nerve with a powerful service game to take an enthralling match.
Earlier Tomljanovic, who relocated to Brisbane in November and intends to represent Australia, repaid the organisers who gave her a wildcard as she finished far too strong for former world number one Jankovic.
The 21-year-old Tomljanovic won a tough first set then raced away with the second in just 25 minutes as Jankovic struggled.
Jankovic said she had still to regain full fitness after suffering a back injury towards the end of 2014.
"I was not playing or doing any activities for two months, so it took me a little bit of time to just get active and kind of start doing just normal things, and then kind of getting to the tennis and training properly," she said.
"It's not easy. And after not competing, after just practising and just trying to get in form and get in shape -- I lost my muscles and I looked like jelly. You know, there was nothing there."
Jankovic said she thought at one stage her career might be over.
"When you are injured and you have a bad back injury, you're thinking maybe you're never going to be able to play again at a high level," she said.
Australia's Samantha Stosur suffered yet more heartbreak in her home town when she let slip a 5-1 lead in the third set, eventually going down to Varvara Lepchenko of the USA.
Lepchenko won the last six games to beat Stosur 4-6, 6-4, 7-5.
In other matches, seventh-seeded Spaniard Carla Suarez Navarro came from a set down to beat Bulgaria's Tsvetana Pironkova 3-6, 6-2, 6-1. Elina Svitolina of Ukraine was too strong for Slovakia's Magdalena Rybarikova, winning 6-0, 6-2.