Serena Williams lost the women's singles quarterfinals to another American tennis player, Sloane Stephens, at the Australian Open on Wednesday and she didn't handle it very well.

Though Williams owned the first set (3-6), she lost the second (7-5) and injured her back during the final set she lost (6-4.)

After she lost her serve and hurt her back while trying to avoid hitting the net during the third set, Williams walked away from the court with a limp when she decided to take her second timeout in the tournament. Stephens, 19, officially won the match after the linesman called Williams out for a foot fault.

Stephens is the first American player younger than Williams to ever beat her.

When Williams' loss to Stephens was confirmed, the 15-time Grand Slam champion slammed her tennis racket on the ground twice and hard. After she destroyed the racket, Williams threw it at her tennis bag.

Beating Williams is the greatest victory of Stephens' career thus far and the win helped her earn a No. 25 rank in the pro league. She is also the youngest woman currently ranked in the WTA (Women's Tennis Association) Top 40 list. 

After the match, Stephens' Twitter follower count rose from 17,000 to 45,000 and counting. She also received tweets from fellow athletes, including former basketball star NBA star Shaquille O'Neal who told her "When you defeat a legend, you become a legend. Keep it going."

Stephens earned 500,000 Australian dollars (U.S. $526,793) for beating Williams and reaching the semifinals. Thanks to the win, she has now advanced to the semifinals and will face WTA's No. 1 ranked Victoria Azarenka. It will be the first Grand Slam appearance for Stephens, a Florida native.

Watch the video of Williams break her tennis racket in her upset loss to Stephens.

Tags: Australian Open 2013 Sloane Stephens Serena Williams