The US Open turned over Arthur Ashe Stadium to the Williams sisters on Thursday for a prime-time first round doubles match that could have been Serena's last after the pair fell 7-6 (5) 6-4 to the Czech duo of Lucie Hradecka and Linda Noskova.
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.
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.
But Flushing Meadows has not seen the last of Serena just yet, with the 40-year-old back in action on Arthur Ashe on Friday for an eagerly anticipated third round singles clash with Australia's Ajla Tomljanovic.