Serena Williams is a champion's champion. Even at age 31, she engenders fear in her foes as she combats their dreams of beating a legend.
While Serena has said playing doubles keeps her sharp for singles matches, the only thing that seemed sharp about Monday's match was the pain in her already ginger ankle after re-tweaking it.
Though the doubles loss falls more squarely on the shoulders of Venus, Serena certainly didn't help matters, limping around tentatively throughout the match while expressing obvious pain through scrunch-faced grimaces.
This begs the question as to whether Serena should be playing doubles in major tournaments as well as how much this affects her chances at winning her 16th Grand Slam.
Will she be able to retrieve serves and trade powerful groundstrokes with 19-year-old Sloane Stephens, aka "Little Serena," in the quarterfinal?
While she seemed to bounce back nicely from the injury earlier in the tournament—finishing off Edina Gallovits-Hall before abusing Garbine Murguruza and Ayumi Morita in the 2nd and 3rd rounds, respectively—one has to wonder how her ankle will hold up after a two and a half hour match that must have seemed like a marathon.
Will fatigue be a factor for the 31-year-old Williams?
She's definitely one of the fittest, if not the fittest, female on tour, but playing for such an extended period of time on an injured ankle certainly won't improve her chances at a title.
Still, Serena has proven time and time again that the only person who can stop her is herself...and occasionally her sister.
So, regardless of injury, fatigue and the fresh, powerful 19-year-old eager to face her idol in the quarterfinal, the only thing standing in the way of Serena's fifth Australian Open title is Serena.