Defending champion Serena Williams continued her march towards a sixth Wimbledon title with a straightforward 6-3 6-2 second-round win over French teenager Caroline Garcia.

Top seed Williams won the first set in 30 minutes on No. 1 Court against the 19-year-old Garcia who put up more of a fight than expected on a bright day at the All England Club.

The 31-year-old American, who beat Garcia en route to winning the French Open earlier this month, easily wrapped up victory against the world number 100 to take her unbeaten run to 33 matches.

Williams, a 16-times grand slam winner, will next face Japan's 42-year-old Kimiko Date-Krumm.

Date-Krumm, the grand old lady of the women's singles draw, became the oldest female player to reach the Wimbledon third round in the professional era.

The 42-year-old, one of 13 players aged over 30 in the main draw but the oldest by a distance, was too wily for 23-year-old Romanian Alexandra Cadantu in a 6-4 7-5 victory.

It is the first time Date-Krumm, ranked 84, has reached the Wimbledon third round since 1996 when she made the semi-finals.

She is the oldest woman to progress to this stage since Britain's Virginia Wade, aged 39 years, in 1985.

The oldest man to reach the third round at Wimbledon since the game went professional in 1968 is Australia's Frank Sedgman who was 43 at the time in 1971.