JOIN USDjokovic takes out Berdych
Djokovic won 6-7, 6-2, 4-2 in a fluctuating tussle with the third-seeded Czech who was hampered by a thigh injury in the closing stages.
The pair were evenly matched in the opening set with neither earning a break point in the first 11 games but Djokovic saved two set points before losing the tiebreak 7-5.
Games went quickly in the final set as both players held serve comfortably until Djokovic broke to lead 4-3. Berdych lost the next two points before deciding to retire.
“The problem was my left quadriceps,” Berdych told reporters. “Was not able just to serve, move to the sides, and just feel the pain. It's no chance to just play this guy in the condition that I was feeling.
Djokovic will play either top seed and four-times former champion Roger Federer or unseeded Richard Gasquet, who clash later on Friday, in Saturday's final.
Federer scored a 6-3, 6-4 win over defeated Ukraine’s Sergiy Stakhovsky on Thursday.
Wozniacki through
World number one Caroline Wozniacki reeled off 12 successive games to ease into the semifinals of the Qatar Open after a 6-2 6-0 demolition of Italian Flavia Pennetta on Thursday.
Second seed and world number three Vera Zvonereva was made to work harder for her semifinal spot after a 7-5, 6-7, 7-5 win over Slovakia's Daniela Hantuchova in a match that lasted more than three hours.
Having lost the opening two games, Dane Wozniacki did not drop another in a ruthless display to remain on course for a second straight title.
Wozniacki next faces Marion Bartoli after the Frenchwoman swatted aside China's Peng Shuai 6-2, 6-2. Russian Zvonereva will play Jelena Jankovic for a place in the final after the Serb downed Czech Klara Zakopalova 6-2, 6-4.