01 September,2012 07:49 AM IST | | AFP
The loss made this the first year in Williams' pro career, which began in 1997, that she has not gone past the second round in any Grand Slam tournament. "Losing a match like this isn't a lot of fun, but that's sport," Williams said.
Williams missed a chance to avenge a third-round loss to Kerber at the London Olympics.
Meanwhile, Serena Williams registered a 6-2, 6-4 win over Spain's Maria Jose Martinez Sanchez to book a spot in the third round.
Serbia's Ana Ivanovic also reached the third round with a 6-2, 6-2 win over Sofia Arvidsson of Sweden.
Second seed Agnieszka Radwanska almost suffered a fourth successive second-round exit before fighting back from a set and 3-1 down to beat Spain's Carla Suarez-Navarro 4-6, 6-3, 6-0.
In the men's event, French fifth seed Jo-Wilfried Tsonga crashed out to his worst Grand Slam showing in more than five years with a second-round 6-4, 1-6, 6-1, 6-3 defeat at the hands of unheralded Martin Klizan. u00a0