(CNN) -- Rising young star Victoria Azarenka of the Belarus made a shock second round exit in the WTA tournament in Stuttgart to Gisela Dulko.
Jankovic was all smiles after a straight sets stroll against Cibulkova.
The fourth seed, who came into the Porsche Grand Prix event off the back of three tournament wins this season, including the Miami Masters, found her match against clay court specialist Dulko.
The Argentine relished the conditions in the only indoor clay event on the circuit to send Azarenka packing 6-4 6-3 on Wednesday.
There were no such problems for defending champion Jelena Jankovic who needed a fraction over an hour to beat Slovakian teenager Dominika Cibulkova 6-1 6-1 to reach the second round.
Jankovic has slipped from the top of the world rankings to fourth, but showed her best form at the start of her title defense.
Fifth seed Svetlana Kuznetsova of Russia had a harder task against German qualifier Andrea Petkovic, winning 6-4 5-7 6-1.
Fellow Russian Nadia Petrova also needed three sets to beat Zheng Jie of China 6-4 5-7 6-4 while Slovak Daniela Hantuchova of Slovakia saw off Alize Cornet of France 6-3 6-1.
In the WTA tournament in Morocco, top seed Anabel Medina Garrigues of Spain, reached the quarterfinals with a 1-6 7-6 6-3 win over Klara Zakopalova of the Czech Republic 1-6 7-6 6-3.
Medina Garrigues lost in last year's final to Azarenka's Stuttgart conqueror Dulko.
Second seed Alisa Kleybanova of Russia also came safely through against Jarmila Groth of Slovakia 6-4 6-1.