Radwanska went right to work from there, hitting the corners with her pinpoint groundstrokes more and more and capitalizing on the unforced errors that began creeping into Muguruza's game, and after two hours and 38 minutes - and some tense moments as she watched a 4-1 third set lead dissipate to 4-all - the No.5-seeded Pole finally got the better of the No.2-seeded Spaniard, 6-7(5), 6-3, 7-5.
Radwanska, who finished the match with 29 winners to 24 unforced errors, was visibly emotional afterwards, and those tears of joy continued as she spoke to the fans in her on-court interview.
"I have no words to say really," Radwanska said as the adoring crowd cheered her on.
"I didn't know if I could come back after that first set, but I think it was a great match from the beginning until the end, so many rallies and a lot of running.
I'm just so glad I could win this match in the end.