"That was such an astounding, absolutely monumental upset in women's tennis," Austin told BBC Sport. "I don't remember a day ever in Grand Slam history like the first Wednesday [when Roger Federer lost] and then you add in this huge upset and it's really quite shocking.
"Very few athletes have gone into an event as much an overwhelming favourite as Serena Williams was here at Wimbledon. To put it in context, Serena came into the match off the back of 34 straight wins. She won Wimbledon last year, the Olympics, the US Open and six titles this year including the French Open. That's quite a streak.
"Plus, with the draw opening up following her two biggest contenders - Victoria Azarenka and Maria Sharapova - going out then this was her title for sure. This result is going to take a while to digest as it is certainly the shock of the decade."
Williams has won five Wimbledon titles in her career so far.