Yesterday, as promised, was an exciting day of tennis at Wimbledon. Serena Williams faced, and defeated gracefully, elder sister Venus. Roger Federer advanced to the quarterfinals with an impressive showing of skill, patience and nerve, as did Andy Murray. And defending champion Novak Djokovic (pictured), after losing the first two sets in tough tiebreakers to towering (6’8”), cannon-serving Kevin Anderson, evened the match by taking the next two sets, in a grueling duel that was sto