Miami - Serena Williams crushed a teenaged talent less than half her age on Sunday to reach the fourth round of the ATP and WTA Miami Open, defeating American Catherine Bellis 6-1, 6-1.
The 15-year-old US challenger was no match for the 33-year-old American, a 19-time grand slam champion who is bidding for a record eighth trophy at her home event.
Bellis, the junior world number one, found herself in a major test against the game's current dominator in her first WTA appearance since the US Open, where she upset Dominika Cibulkova.
World number one Williams is competing in Miami for the 15th time since debuting as a teenager herself in 1998, a year before Bellis was born.
Top-seed Williams will next face Russian Svetlana Kuznetsova, a winner over German 13th seed Angelique Kerber 6-3, 3-6, 6-3.
Williams, bidding for a third consecutive Miami title, stretched her win streak to 14 matches at Crandon Park. Her career Miami record now stands at 69-7.
Williams wrapped up the affair in 41 minutes with 15 winners and five breaks of the prodigy's serve. Bellis committed 21 unforced errors.
"If you break down her age and her ability and how well I think she handled the moment and how well she played, I think it was good," Williams said.
"She's young and her being an American, you want to see people like her do well. When you're up against them, you have to kind of put that aside, even though I'm always cheering for her. Otherwise I have to put it aside and play the match."
Williams said that the knee injury which knocked her out of an Indian Wells quarter-final last week continues to improve.
"I've been feeling pretty good, much better than I did in my last tournament. I've surpassed my expectations," Williams said. "When I'm out there I don't feel it as much. It feels a little better every day."
Third seed Simona Halep defeated Italy's Camila Giorgi 6-4, 7-5 to continue the momentum she took from last week's title at Indian Wells. The Romanian overcame five double-faults in a victory requiring nearly 90 minutes.
Halep is bidding for a fourth WTA title this season after winning at Shenzhen, Dubai and Indian Wells.
Italian 15th seed Flavia Pennetta defeated two-time Miami champion Victoria Azarenka 7-6 (7/5), 7-6 (8/6).
In the men's draw, Britain's Andy Murray won his 499th career match, downing Colombian Santiago Giraldo 6-3, 6-4 to reach the fourth round.
The 27-year-old Scotsman, who won the Miami title in 2009 and 2013, would become the ninth active player to reach 500 victories if he wins his next match against South African 15th seed Kevin Anderson, who eliminated Argentina's Leonardo Mayer 6-4, 6-4.
"Hopefully I can win some more throughout my career," Murray said. "Maybe it doesn't happen in a couple of days. I hope it does. But if not, then, you know, I'm sure at some stage I will get there.
"I obviously want to try and win more, and hopefully still have quite a few years ahead of me left to add to that number. It's a lot of wins. It's not easy these days to win that many matches, so that's a good sign."
Murray was pleased with his showing.
"I played well, I thought it was a good performance. I hit the ball pretty clean," he said. "He came out and started swinging a bit towards the end of the match and made it a little bit tricky, but I thought for the most part I played very well."
Murray won in 84 minutes, breaking three times and hitting 19 winners took advance. Against Anderson, Murray has three wins from four matches, the last in Valencia last year.
France's 32nd-ranked Adrian Mannarino won his first match in 13 attempts against a top 10 opponent as he stunned an off-form Stan Wawrinka, the seventh seed, 7-6 (7/4), 7-6 (7/5), while Gael Monfils won an all-French match with good friend and 11th seed Jo-Wilfried Tsonga 6-4, 7-6 (7/4).
Results on Sunday from the sixth day of the ATP and WTA Miami Open (x denotes seeded player):
Simona Halep (ROM x3) bt Camila Giorgi (ITA x30) 6-4, 7-5
Svetlana Kuznetsova (RUS x24) bt Angelique Kerber (GER x13) 6-3, 3-6, 6-3
Serena Williams (USA x1) bt Catherine Bellis (USA) 6-1, 6-1
Sara Errani (ITA x11) bt Garbine Muguruza (ESP x21) 4-6, 6-4, 6-1
Flavia Pennetta (ITA x15) bt Victoria Azarenka (BLR) 7-6 (7/5), 7-6 (8/6)
Sloane Stephens (USA) bt Johanna Larsson (SWE) 6-4, 6-4
Belinda Bencic (SUI) bt Tatjana Malek (GER) 6-4, 7-5
Sabine Lisicki (GER x27) bt Ana Ivanovic (SRB) 7-6 (7/4), 7-5
Kevin Anderson (RSA x15) bt Leonardo Mayer (ARG x24) 6-4, 6-4
Andy Murray (GBR x3) bt Santiago Giraldo (COL x27) 6-3, 6-4
Dominic Thiem (AUT) bt Jack Sock (USA) 6-4, 6-3
Adrian Mannarino (FRA x28) bt Stan Wawrinka (SUI x7) 7-6 (7/4), 7-6 (7/5)
Gael Monfils (FRA x17) bt Jo-Wilfried Tsonga (FRA x11) 6-4, 7-6 (7/4)
Fernando Verdasco (ESP x29) bt Rafael Nadal (ESP x2) 6-4, 2-6, 6-3
Tomas Berdych (CZE x8) bt Bernard Tomic (AUS) 6-7 (4/7), 7-6 (7/3), 6-1
Juan Monaco (ARG) bt Guillermo Garcia-Lopez (ESP x23) 7-5, 6-4