Winners of 14 Grand Slam doubles titles, including two US Opens, the Williams sisters were playing together for the first time in more than four years, the occasion attracting a capacity crowd to watch one of tennis's most successful partnerships take perhaps a final bow.
If it was indeed the last time the Williams sisters would stand shoulder-to-shoulder on court, the end came with little sentiment or emotion. The two greats embraced briefly at the net then stoically packed their bags, exited to a standing ovation and offered only a gentle wave to the cheering crowd.
"I'm so sorry for you that we beat them, but we are so happy that we did it," apologised Hradecka to the crowd after the match. "I'm still in shock."
Serena signalled her intention to retire in a Vogue article in early August, saying she was "evolving away from tennis" but never confirming the US Open as her final event.
Flushing Meadows, however, has not seen the last of Serena just yet, as she is back in action on Arthur Ashe on September 2nd for an eagerly anticipated third-round singles clash with Australia's Ajla Tomljanovic.
The prime-time doubles match reminded tennis once again of the immense popularity of the Williams sisters and the absolute hold they have on the sport.
Doubles are seldom seen during the early rounds on Arthur Ashe, usually banished to the outside courts until the men's and women's, or mixed doubles finals when they are brought in as opening acts for the main events.
Even then those Grand Slam championship contests are played in a mostly empty stadium to entertain early arrivals for the men's and women's finals.
But on Thursday the world's biggest tennis stadium was packed to the rafters with Venus (42) and Serena joining forces for their first US Open since 2014.
With the exception of perhaps Roger Federer and Rafa Nadal - if they were to form a doubles partnership - it is doubtful any other players could cause the United States Tennis Association (USTA) to consider turning over the prime-time evening slot to a doubles match.
"You have Venus and Serena playing for first time here in eight years there's a demand to see that," USTA spokesman Chris Widmaier told Reuters about the decision to put doubles on the main show court. "There's also the fans that aren't here, they want to see that on television.
"To us it was the obvious thing to do."
