Andy Murray reaches Miami Open last 16 but Rafael Nadal out

Murray lives and trains in Miami for much of the year

Andy Murray dismantled Colombian Santiago Giraldo's hard-hitting game to claim his 499th career win and reach round four at the Miami Open.

The Briton, seeded third, won 6-3 6-4 and will play South Africa's 15th seed Kevin Anderson in the last 16.

Another victory would make Murray the 46th man in the open era to reach 500 match wins.

Fernando Verdasco beat Rafael Nadal 6-4 2-6 6-3, while women's top seed Serena Williams beat Cici Bellis 6-1 6-1.

Murray, 27, lost heavily to Giraldo in Madrid last year but made amends in Miami, where he lives and trains for much of the year.

The Scot attacked his opponent's second serve from the outset, breaking in game six on his way to the first set and then powering 4-0 clear in the second.

There was a late revival from the now free-swinging Giraldo, who saved two match points and broke serve at 5-2 and saw off another two at 5-4.

It delayed Murray but did not derail him, and the world number four finally sealed victory at the fifth attempt thanks to a net cord.

Looking ahead to a potential landmark win on Tuesday, Murray told BBC Sport: "Getting to 500 wins is a lot. There's not loads of players that have done it.

"Hopefully it happens in a couple of days, if not then hopefully later on in the year I'll win another match and have the opportunity to win many more.

"It's a nice milestone to reach when I get there."

Murray's coach Amelie Mauresmo (left) and fiancee Kim Sears (right) were courtside in Miami

Nadal goes out to Verdasco

Rafael Nadal admitted he was "playing with too much nerves" after losing 6-4 2-6 6-3 to fellow Spaniard Fernando Verdasco.

World number 34 Verdasco, 31, has now won his last two matches against Nadal.

The second seed said recent injury problems were not to blame for his exit, and explained: "The physical problems are in the past. Now I need to fix again the nerves, the self-control on court.

"I'm going to fix it, I don't know if in one week, in six months, or in one year, but I'm going to do it."

Serena thrashes 15-year-old Bellis

Serena Williams took just 42 minutes to see off 15-year-old wildcard Cici Bellis, the junior world number one.

Bellis, ranked 211th by the WTA, remains an amateur despite beating Dominika Cibulkova at the US Open last year, and she saw off 29th seed Zarina Diyas in her opening match in Miami.

Williams, 18 years older than her compatriot, was not about to fall victim to another upset and won 6-1 6-1 in windy conditions.

"It was a good match, she plays really well and I'm just out here trying to take the title," said Williams. "It's just good to see another American doing well."

Bellis first made headlines when she beat 12th seed Cibulkova at last year's US Open

Best of the rest

Gael Monfils saw off fellow Frenchman Jo-Wilfried Tsonga 6-4 7-6 (7-4), and compatriot Adrian Mannarino beat seventh seed Stan Wawrinka of Switzerland.

Eighth seed Tomas Berdych, of the Czech Republic, beat Australia's Bernard Tomic 6-7 (4-7) 7-6 (7-3) 6-1.

In the women's draw, Serbian fifth seed Ana Ivanovic was beaten 7-6 (7-4) 7-5 by German Sabine Lisicki and third seed Simona Halep, of Romania, defeated Italian Camila Giorgi 6-4, 7-5.

Italy's Flavia Pennetta, the 15th seed, defeated two-time champion Victoria Azarenka of Belarus 7-6 (7-5) 7-6 (8-6).