Here's a short story:

(CNN) -- At times it was almost painful to watch. At one end of the court the world's No. 1 female tennis star playing well within herself; at the other her sister, a long way away from regaining that form and status. 

"Venus has had a great week, and honestly, if she hadn't had to play so many matches, it would have been a much tougher match," Serena Williams said after comfortably beating her older sibling on Saturday to reach the final of the Family Circle Cup in Charleston. 

The 31-year-old was slightly overstating the rigors of the competition in South Carolina, a tournament that heralded the formation of the women's tour back in 1973 but has this week attracted just two of the world's top-10 players. 

Serena is one, and the other -- 10th-ranked Caroline Wozniacki -- crashed out in the quarterfinals on Friday against Swiss No. 63 Stefanie Vogele. 

Both Williams sisters won two matches on Friday to set up their first meeting since 2009, but it was defending champion Serena who looked the least affected as she won 6-1 6-2 in just 54 minutes. 

"She'll never admit it, but I don't think she was 100%," Serena said of her sister, who was diagnosed with a debilitating autoimmune disease before the 2011 U.S. Open -- a grand slam she has won twice, along with her five Wimbledons. 

"But you will never get that out of her. And quite frankly, three matches for her is much tougher than three matches for me. It's definitely not easy -- because I'm struggling, and I can't imagine what she must be feeling."  (End of story)

Provide your best guess for the following question. Give ONLY the guess, no other words or explanation.

For example:

Guess: <most likely guess, as short as possible; not a complete sentence, just the guess!>

Here are a few examples of questions and answers:

Question: Who played the match in question?
Guess: the world's No. 1 female tennis star

Question: What is her name?
Guess: Serena Williams

Question: Who was she competing against?
Guess: her sister

Question: What's her name?
Guess: Venus

Question: Where did this event take place?
Guess: Charleston

Question: What was the name of the event?
Guess: Family Circle Cup

Question: Who was the other high ranked player there?
Guess: Caroline Wozniacki

Question: What was her rank?
Guess: 10th

Question: Did she win the event?
Guess: No

Now answer the following question in the same format.

Question: Who did she lose to?

Stefanie Vogele