Montreal, QC -- (Sports Network) - Second-seeded Jelena Jankovic's journey to the world Number 1 ranking took an unexpected detour Friday at the $1.34 million Rogers Cup.

Unranked Slovakian Dominika Cibulkova posted a straight-set 7-5, 6-2 victory over the super Serb. Jankovic had rolled into the quarterfinals with a 6-3, 6-2 rout of Canadian Stephanie Dubois, and could have attained the top rank with an appearance in the final on Sunday.

Cibulkova, who took out 12th-seeded Russian Nadia Petrova 7-6 (7-2), 6-2, goes to the semifinal on Saturday to face Italy's Marion Bartoli.

It was the second shock to high seeds in the tournament in as many days, as Ana Ivanovic fell in stunning fashion to 17-year-old Austrian Tamira Paszek in third-round action Thursday. The top seed looked flat in her first event since a surprisingly early third-round exit at Wimbledon. Paszek took advantage for a 6-2, 1-6, 6-2 victory -- her first-ever victory over a top-10 player.

The athletic Jankovic was last year's Rogers Cup runner-up to Justine Henin, in Toronto. This tournament shifts between Montreal and Toronto each year.

In other action, seventh-ranked Dinara Safina defeated fellow Russian and last year's U.S. Open runner-up Svetlana Kuznetsova 2-6, 6-3, 6-2. 10-seed Bartoli rolled to a 6-2, 6-3 win over Ai Sugiyama, and 11th-seed Victoria Azarenka stopped Paszek's run with a 6-4, 7-5 triumph and faces Safina in the semis.

The 2008 Rogers Cup titlist will collect $196,900.