Ivanovic beat seventh-seeded Flavia Pennetta of Italy 6-4, 6-4, second-seeded Vera Zvonareva defeated eighth-seeded Alize Cornet of France 7-5, 6-1, and third-seeded Agnieszka Radwanska stopped fifth-seeded Nadia Petrova of Russia 6-3, 6-2.
They were joined by sixth-seeded Marion Bartoli, who beat the only unseeded player to make the last eight, Alona Bondarenko of Ukraine, 6-3, 5-7, 6-1.
Ivanovic broke Pennetta, last week's runner-up in Zurich, at 4-4 and added three more breaks in the second set.
"It was a difficult match,'' Ivanovic said. "I was never sure if I did enough to beat her.''
In Zurich, the Serb had reached her first semifinals since winning the French Open, and her second last-four effort in two weeks showed she was past her thigh and thumb injuries. Ivanovic will play Radwanska on Saturday.
Radwanska stayed on course for a fourth WTA Tour title this season by routing 2005 champion Petrova.
The 10th-ranked Pole, who won only three games against Petrova in their previous meeting this season, broke the Russian four times.
Zvonareva used powerful serves and groundstrokes against Cornet, who won her first WTA title in Budapest in July.
The victory earned Zvonareva a berth in the season-ending WTA Championships for the third time, and first since 2005.
"It was a long road to Doha and I am very happy that I finally made it,'' Zvonareva said.
Her next opponent is Bartoli, who improved to 3-0 against Bondarenko.
Ivanovic, Zvonareva, Radwanska reach semifinals
Advocaat: We Can Beat Juve & Madrid
