Novak Djokovic advanced to the semifinals of the BNP Paribas Open on Thursday when opponent Bernard Tomic withdrew because of a back injury.

Tomic's withdrawal was announced about five hours before he was to play Djokovic, a three-time champion at Indian Wells who has won his first three matches in straight sets. He has beaten Tomic each of the three times they've played.

Tomic had gotten off to a strong start this year, reaching the quarterfinals at six of the seven tournaments he's played. The exception was the Australian Open, where he lost in the fourth round. The Australian defeated sixth-seeded David Ferrer in straight sets in the third round here, Tomic's first win over a Top 10 player since July 2013.

Jelena Jankovic reached the women's semifinals when qualifier Lesia Tsurenko retired in the second set with a foot injury.