Anett Kontaveit powered past third-seeded Karolina Pliskova 6-4, 6-0 on Friday to lead the way into the semi-finals of the season-ending WTA Finals.
The eighth-seeded Estonian notched her 12th straight WTA match win as she assured herself of finishing in the top two of her group in the round-robin phase.
Kontaveit, whose win streak included titles at Moscow and Cluj-Napoca, had beaten French Open champion Barbora Krejcikova in her tournament opener.
She needed just 57 minutes to roar past Pliskova, winning 24 of her 29 first-service points and claiming the last eight games for her first career victory over the Czech in four meetings.
Group action continued later Friday with Krejcikova taking on Garbine Muguruza.
The elite tournament was moved to Guadalajara this year from its usual home in Shenzhen, China, due to the coronavirus pandemic.
World number one Ashleigh Barty of Australia is not defending her title because of continuing pandemic travel restrictions.