The 23 time Grand Slam winning champion failed to lift a major title since her return past year.
As for Monday's match against Diatchenko, Williams got off to a slow start, committing 14 unforced errors before dropping the first set 2-6.
That goal seemed even further from her grasp with the way things began in Court Philippe Chatrier against Diatchenko, a Russian who hits two-fisted shots off both sides and upset Maria Sharapova at Wimbledon past year. I knew that I couldn't get worse. As the three-time French Open singles champion played, the Twitterverse debated the merits of her outfit.
Williams downplayed the comments at the US Open, saying she no longer needed to wear the leggings because she found that compression tights also work to keep her blood circulating.
She produced a see-saw display in an half-empty stadium on Monday, struggling to adapt to windy conditions in chilly weather.
A year ago, Williams elicited audible gasps from the Chatrier crowd when she returned to her first major since becoming a mother, clad in a sleek, black catsuit, form-fitting from ankles to neck, with a bold red band at the midsection. "It was just a unusual start to that match, for me".
Certainly her movement was not at its peak against Diatchenko.
"Mother, Champion, Queen, Goddess", these some of the words emblazoned in French on Williams's stunning tennis outfit.
Then former world No. 1 Caroline Wozniacki departed in three sets to Diatchenko's countrywoman, Veronica Kudermetova, 0-6 6-3 6-3. The American and the Russian have met only once before, at the 2015 US Open, where Diatchenko had to retire hurt and Serena won the match after leading in the first set.
Williams has become equally well known for her stand-out court style as much as her sporting prowess in recent years.
She swept through the decider, breaking in the first, third and fifth games. This is who I am now, the outfit said.
"Physically I felt pretty good".
The quest for perfection has always defined Nadal and the win improved his Roland Garros record to a remarkable 87-2.
But No. 32 seed Frances Tiafoe of the Untied States, a quarter-finalist at the Australian Open in January, threw up a couple of times and his game came apart late in a 6-2, 4-6, 6-3, 3-6, 6-0 loss to Filip Krajinovic of Serbia.