Precocious amateur CiCi Bellis says she 's ready to take on the best of the pros - Serena Williams . Bellis , a 15-year-old American who made a big splash at last year 's U.S. Open , advanced Friday to a potential third-round match against Williams by beating Zarina Diyas 6-2 , 6-1 . Williams ' second-round match Friday night against Monica Niculescu was postponed until Saturday because of rain . But Bellis was already relishing the chance to take on the 19-time Grand Slam champion . Catherine `` CiCi ' Bellis of the United States , pictured at the US OPen this summer , advannced at the Miami Open on Friday and may have a chance to go against Serena Williams . 'It 's going to be really fun , ' Bellis said . ' I have nothing to lose , so I 'm just going to play my game and see what happens . ' Sloane Stephens won an all-American match on the stadium court , converting five of six break-point chances to beat No . 17 Madison Keys 6-4 , 6-2 . It was the first meeting between the two Fed Cup teammates , and Keys teared up near the end of her loss . ' I just kind of let the emotions get to me , ' the 20-year-old Keys said . 'It 's like you 're having a really terrible day , but my terrible day is in front of hundreds of people and then broadcast on TV . That 's not always fun . ' New opponent ? : CiCi Bellis Bellis is already relishing the chance to take on the 19-time Grand Slam champion Serena Williams ( pictured ) after her recent win against Zarina Diyas . No . 2-seeded Rafael Nadal , showing no ill effects from an ankle injury suffered in practice Monday , defeated fellow Spaniard Nicolas Almagro 6-4 , 6-2 . ' I am well , ' Nadal said . 'The day after , I had pain , but after two days I improved 50 percent . It 's not limiting my movements . ' Others advancing in the women 's draw included No . 3 Simona Halep , the titlist last week at Indian Wells . She won 6-4 , 2-6 , 6-1 against wild card Nicole Vaidisova , a two-time Grand Slam semifinalist mounting a comeback from two shoulder operations . Two-time champion Andy Murray beat American Donald Young 6-4 , 6-2 . Other men 's winners included No . 7 Stan Wawrinka , No . 8 Tomas Berdych and No . 25 Bernard Tomic . American Sam Querrey had 19 aces but lost to No . 15 Kevin Anderson 6-7 ( 5 ) , 7-6 ( 3 ) , 6-4 . No . 10 Feliciano Lopez was eliminated by Dominic Thiem , 7-6 ( 4 ) , 4-6 , 6-3 . Four-time champion Novak Djokovic lost in doubles and plays his opening singles match Saturday night . 'Hopefully I can have another great week in Miami , ' Djokovic said . Zarina Diyas of Kazakhstan shakes hands with Catherine `` CiCi ' Bellis of the United States at the US Open last year and on Friday at the Miami Open Bellis beat Diyas 6-2 , 6-1 . 'Some of my best tennis I have played here in these courts . ' Two-time champion Victoria Azarenka reached the third round by beating No . 20 Jelena Jankovic 6-1 , 6-1 . Azarenka faced 13 break points and saved them all . ' I stayed composed , ' Azarenka said . ' I was very sure what I had to do , and I was really executing that . ' Bellis became the youngest player to win a match at the U.S. Open since 1996 when she upset 12th-seeded Dominika Cibulkova last August . Suddenly a celebrity , Bellis then lost to Diyas in the second round . She avenged that defeat Friday with much less fanfare . 'This one I think I played a lot smarter , ' Bellis said . Oppents : Zarina Diyas of Kazakhstan returns a shot against Catherine `` CiCi ' Bellis of the United Statesduring their women 's singles second round match on Day Four of the 2014 US Open last year . 'At the U.S. Open I was really like caught up in all the kind of hype that was going on . But this one I was just really focused and played my game . I think I did what I needed to do to win really well . ' The Californian has yet to turn pro , and the Miami Open is her biggest tournament since the U.S. Open . She made the draw as a wild card and played Friday on remote Court 9 , but she 'll be on the stadium court Sunday if she faces Williams , who has won Key Biscayne a record seven times . Intimidating ? Bellis says no . 'We are all in the same tournament , so we are all kind of at this level , ' she said . 'You ca n't really think about who you 're playing . It 's just a ball that 's coming back on the other side of the court . You just have to go out and not think about that stuff and just play your game . That 's what I 'm planning to do . '
CiCi Bellis , a 15-year-old Californian , advanced on Friday to a potential third-round match against Serena Williams by beating Zarina Diyas 6-2 , 6-1 . ' I have nothing to lose , so I 'm just going to play my game and see what happens , ' said of her potential match with Serena Williams . 'You ca n't really think about who you 're playing . It 's just a ball that 's coming back on the other side of the court , ' said Bellis .