Serena Williams enters the US Open with a chance to surpass Steffi Graf for the record of most Grand Slam titles. The duo are locked at 21, after Williams owned Wimbledon in July. Wimbledon might have been Williams' 22nd title, if it weren't for an upset-minded Italian named Roberta Vinci last fall. Vinci sent oddsmakers into a frenzy as she beat Williams -- an enormous favorite -- in the semifinals of what looked to be a surefire Williams waltz to glory. The Vinci defeat stole Williams' chance for a calendar Grand Slam in 2015.
Serena is again seeded No. 1 in New York for the 2016 Open. This time when she gets to the semifinals there's a chance she'll see a familiar face there -- that of her sister Venus. The No. 6 seed Venus Williams is a tougher opponent than the No. 7 seed Vinci for almost anyone in tennis, except perhaps for Serena, who has made relatively easy work of her older sister in latter years. The sisters have never met in a US Open semifinal, though they've played twice in the final.The BEST SALES on Amazon NOW ]