Halep, the No. 7 seed, eliminated Errani 6-2, 6-0 in 52 minutes. Halep won two-thirds of the points on the day, including 60 percent off Errani's serve. She saved all three break points she faced while going 5-of-7 in her own break opportunities.
Jankovic, at 75 minutes the longest match of the round, lost her serve twice but also had six breaks in eight receiving games.
No. 6-seeded Angelique Kerber needed only 50 minutes to dispatch Petra Cetkovska 6-1, 6-0. The one game she lost came on a service break but she won almost three-quarters of the points off Cetkovska's serve.
Kerber goes against Jankovic in the first semifinal Saturday. They have split their first two career meetings, with Jankovic taking a 6-7 (10-12), 6-3, 6-1 decision this year in Brisbane, Australia. Radwanska won the first three times she played Halep, but Halep beat Radwanska in Rome last year in the most recent pairing.
Swim Week Miami Beach 2014 [PHOTOS]