Serena Williams Upset In U.S. Open Semifinals

Serena Williams was ousted in the semifinals of the U.S. Open on Thursday night for the second year in a row. Williams, the heavy favorite, fell to 10th-seeded Karolina Pliskova of the Czech Republic 2-6, 6-7 (5). Williams was playing on back-to-back nights after winning a three-set quarterfinal match Wednesday. After her loss, Williams' coach said she had injured her knee Wednesday. The loss denied Williams a record-breaking 23rd Grand Slam victory, and will end her 187-week reign as the world's No. 1-ranked female player.

Copyright © 2016 MarketWatch, Inc.