Last night at the US Open was certainly not the first, or second, or even twentieth time the Williams sisters played opposite each other at a tennis tournament. In fact, it was the twenty-seventh, with Serena’s win giving her a 26-11 edge. In recent days, it’s been all Serena, having taken seven of the past eight matches. Last night was a reminder of which sibling would go down in history as the more dominant tennis player. Despite a valiant effort by the 35 year-old Venus, the slightly junior and more athletic Serena rallied for a serviceable three set victory. All which means Serena will now continue into the semifinals as the overwhelming favorite to win this US Open and her 22nd major singles event. That would tie her with Steffi Graf for the most ever, and it would also complete her calendar Grand Slam, winning the Australian, French, Wimbledon, and US Open in the same year. Not that it’s in question, but this title would further enshrine Serena as the greatest women’s tennis player to grace the court. One could certainly argue she’s actually the greatest female athlete in any sport, but that’s a discussion for another time. Regardless of the depth of perspective, Serena’s win over her sister last night was yet another demonstration of athletic grace under pressure.