Iga Swiatek joked "in 20 minutes, I'll be dead" after securing back-to-back wins that booked Poland's place in the Billie Jean King Cup semi-finals. (More Tennis News)
The Poles are through to the last four of the competition for the first time, having come from behind to beat the Czech Republic 2-1.
After Marie Bouzkova defeated Magdalena Frech in the opening singles match, Swiatek pulled Poland level by edging out Linda Noskova 7-6 (7-4) 4-6 7-5 after two hours and 39 minutes.
The five-time major winner returned to court just half an hour later for the doubles decider - and her first in this event since 2019.
Nevertheless, Swiatek was not to be denied, partnering Katarzyna Kawa to a 6-1 6-4 win over Bouzkova and Katerina Siniakova.
"It was an exhausting day, but everything worked," the world number two said. "We did a great job, we won."
