forehand from Williams would end the set after 51 minutes of play.
With her sister and tournament favorite Serena Williams and her husband looking on from the stands, Williams steadied her game in set two to strike several powerful forehands and serves to take a 5-3 lead.
Muchova held serve to reach 5-4 which sent Williams to serve for the set.
However in the following game, Muchova struck two forehand winners while Williams committed two crosscourt backhand errors to drop serve and level the set at 5 games all.
Williams then struck three groundstroke errors as The Czech went ahead 6-5.
Serving to stay in the match, the American committed two forehand errors to trail 0-30 before Muchova struck a down the line forehand winner to reach 15-40.
Williams would doublefault on the second matchpoint of the night to end the match after one hour and 48 minutes of play.