MIAMI – Scottish fourth seed Andy Murray and women's world number one and two-time defending champion Serena Williams each advanced to the third round of the WTA and ATP tournament here with triumphs Saturday.

Murray dispatched 59th-ranked Juan Monaco of Argentina 4-6, 6-3, 6-2 while Williams, seeking her sixth title here in eight years, ousted 19-year-old fellow American Alexa Glatch 6-2, 6-3.

Murray, who reached last week's final at Indian Wells, will next face Chile's Nicolas Massu, who battled back to defeat US 27th seed Mardy Fish 5-7, 7-6 (7/4), 6-2.

Williams, who like Murray enjoyed a first-round bye as a seed, booked a third-round date against China's Peng Shuai at the 4.5 million-dollar event.

Williams, 27, won her 10th Grand Slam title in January at the Australian Open and has three other semi-final runs this season. She could face older sister Venus Williams, the reigning Wimbledon champion, in a semi-final.

Improving to 48-5 at the event for her career, Williams shook off first-match nerves for the triumph.

"I played OK," Williams said. "I definitely think I could have played better. Just a little jitters going out there.

"Alexa played well. She has a really good game," Williams said. "She's really young, so she has a bright future."