"I definitely was playing better in the second set but she just seemed to have all the answers," Williams said. "Some days that's how it is. Hopefully, I will have more luck in the next ones."
Pliskova beats Williams for 1st win at WTA Finals →
Since her first full season on the WTA Tour in 1995, Williams says she's seen improvement in the sport.
Venus Williams returns to WTA Finals for 1st time since 2009 →