Tomljanovic in form
On the other hand, the 29-year-old is playing the best tennis of her life. Tomljanovic made it to the quarterfinals at Wimbledon for the second straight year (her career best in the majors), and has now won 11 of her past 12 matches.
A victory over Tomljanovic would have made Serena the oldest woman to reach a Grand Slam round-of-16 in the Open Era that comprises more than a half-century.
Sisters act
Earlier, Serena's doubles campaign ended when she and sister Venus Williams lost in what appeared to be their last doubles match on Thursday night at the sold-out Arthur Ashe Stadium.
They quickly packed their bags, waved briefly to the crowd and walked together to the locker room as the novel pairing of 37-year-old Lucie Hradecka and 17-year-old Linda Noskova of the Czech Republic was too much in a 7-6 (7-5), 6-4 win.
Collective groan
On Friday night, after a collective groan in the sold-out Arthur Ashe Stadium, the crowd rose to their feet to pay their respect to the greatest women's tennis player of all time in her final outing at the US Open, as she treated the crowd to one more of her famous twirls at the Grand Slam she has won six times.
Serena ended up going down in a match that lasted three hours and seven minutes, with a 15-minute final game where the 40-year-old saved five match points illustrating her fighting spirit down to the last moments.
Adios champ!
With 23 major singles titles, Serena remained just one shy of Margaret Court's all-time record and was eyeing one last shot at matching the Australian at the Grand Slam event of the year. But it wasn't to be as Tomljanovic had other ideas.
It may be recalled that Serena had announced to the world on August 9 that she was getting ready to step away from her playing career. Adios champ!