Russians Elena Dementieva and Dinara Safina have the job of solving the puzzle that's so far proved beyond anyone else in the women's draw at Wimbledon this year - How do you stop the Williams sisters?
Venus and Serena are no course for a fourth all-Williams final, whereas Safina the world number one and Dementieva are hoping to set up the first all-Russian fianl.
Despite being the world number one, Safina's expected to be little more than a stepping stone for third seed Venus, who's chasing a sixth Wimbledon title and hasn't dropped a set at the tournament since the 2007 third round.
Dementieva the Olympic champion and world number four may feel somewhat more confident in her battle against Serena - as she's won four of their last five encounters.
