The All England Club has denied suggestions that the Wimbledon courts are too slippery, on a day when seven players withdrew with injuries.
Maria Sharapova fell three times and asked for a medical timeout during her straight-set loss to world number 131 Michelle Larcher De Brito.
Victoria Azarenka pulled out before her match with Flavia Pennetta because of a knee injury sustained during a slip in her first round clash.
Richard Lewis, chief executive of the All England Club, said the lawns were "as they should be" and rejected suggestions that the court surface was to blame for the injuries.
Andy Murray reached the third round"We have no reason to think this is the case. Indeed, many players have complimented us on the very good condition of the courts," he said in a statement.
"The court preparation has been to exactly the same meticulous standard as in previous years and it is well known that grass surfaces tend to be more lush at the start of an event.
"The factual evidence, which is independently checked, is that the courts are almost identical to last year, as dry and firm as they should be, and we expect them to continue to play to their usual high quality."
Andy Murray sailed into the third round with a victory over Lu Yen-hsun while defending champion Roger Federer was stunned by Ukrainian Sergiy Stakhovsky, who is ranked 116 in the world.
But the day was marked by the record-high number of withdrawals and the controversy over the courts.
Sharapova was seen mouthing what appeared to be the words "this court is dangerous" during the match.
Asked about the remark, she said: "After I buckled my knee three times, that's obviously my first reaction."
She described conditions on the court as "slippery" but refused to blame the lawn on Court Two for her defeat, saying conditions were the same for her opponent.
Victoria Azarenka criticised the condition of the courtAzarenka said: "The court was not in a very good condition. My opponent fell twice; I fell badly; there were some other people who fell after."
Former world number one Caroline Wozniacki also slipped and played with tape on her right ankle as she lost to Petra Cetkovska in the second round.
Other players who pulled out were Steve Darcis, who defeated Rafael Nadal in the first round, Jo-Wilfried Tsonga, John Isner, Marin Cilic, Radek Stepanek and Yaroslava Shvedova.
The defeats of Federer and Nadal, and Tsonga's withdrawal leave Murray with a relatively open draw as the Scot seeks to end Britain's 77-year wait for a male champion at All England Club.