The 39-year-old American was beaten 6-3, 7-5 by the 21st seeded, Elena Rybakina, of Kazakhstan.
The last time Williams was able to advance past the fourth round in Paris was in 2016.
Williams says controlling the softer moments is the difference between winning and losing, and downplayed the idea of her days at Roland Garros being numbered.
“Yeah, I'm definitely not thinking about it at all. I'm definitely thinking just about other things but not about that.”
“Yeah, I think I would have just played harder, just played better, I guess? I hate regretting, though.
“It was definitely close. I'm so close. There is literally a point here, a point there, that could change the whole course of the match. I'm not winning those points.”
Meanwhile, in the men’s singles, Roger Federer withdrew from the French Open in order to focus on Wimbledon.
