Azarenka, ranked No. 1 in the world, won the first four and last six games of a 6-1, 6-1 rout of Elena Vesnina. The match took 57 minutes. Azarenka lost only eight points on serve in the first set and, even though she lost her serve in the first game of the second set, dropped just 13 points in the set.
Williams took the last eight games in rolling past 14th-seeded Maria Kirilenko 6-2, 6-0, also in 57 minutes. Williams had just six unforced errors against 22 winners and saved all three break points she faced. She also won 56 percent of the points off Kirilenko's serve.
Unseeded Svetlana Kuznetsova ousted 10th-seeded Caroline Wozniacki 6-2, 2-6, 7-5 with the final set taking 75 minutes, about half the match time of nearly 2 1/2 hours. Wozniacki was able to finish off just one of eight break chances in the third set and Kuznetsova had two of her five breaks in the final set,
No. 29th-seeded Sloane Stephens was on the court about twice as long as Azarenka and Williams in beating Bojana Jovanovski 6-1, 3-6, 7-5 in reaching a Grand Slam quarterfinal for the first time. Stephens had 43 unforced errors and lost her serve five times but offset that with seven breaks, including three in the final set.
Stephens goes against Williams in the quarterfinals. Their only other career meeting was earlier this year, with Williams winning 6-4, 6-3. Kuznetsova is 4-3 versus Azarenka but Azarenka won both meetings last year.
Swim Week Miami Beach 2014 [PHOTOS]