Jon Wertheim: Wimbledon Midterm Grades

We're still on course for Raffa-Roger III and Venus-Serena III C: Perhaps Novak Djokovic should worry about his own vulnerability Jon Wertheim will answer questions from SI.com users in his mailbag every Wednesday. After six days of play, here are our midterm grades from the 2008 version of Wimbledon: A Raffa-Roger III: So far, so good. Venus-Serena III: So far, so good. (And they're cruising in the doubles draw.) WTA depth: Six players outside the top 100 reached Round 3, including giant killers Jie Zheng and Alla Kudryavtseva, who beat Ana Ivanovic and Maria Sharapova, respectively. Marat Safin: Fires up one for the memory banks by beating Novak Djokovic; also impressive, he returns two days later and wins a tight four-setter. Nicole Vaidisova: Apparently shaking off a mean slump, Czech reaches round of 16. Bethanie...