Cristina Bucsa overcame fatigue and rebounded from a disappointing singles loss to help Spain punch their ticket to the Billie Jean King Cup semifinals for the first time since 2008 in Shenzhen on Wednesday.
Bucsa and her teammate Sara Sorribes Tormo secured the deciding doubles point by triumphing 6-2, 7-5 over Anna Danilina and Zhibek Kulambayeva to clinch the quarterfinal tie for Spain over Kazakhstan.
The Spanish pair saved a whopping 18 out of 20 break points throughout the gruelling two-hour, seven-minute doubles affair. The second set alone lasted 88 minutes.
"The girls, they have really good fighting spirit, they put in all their heart and passion. I'm really proud of all of them. But the competition doesn't end here, we have semifinals on Friday," said Spain's team captain Carla Suarez Navarro.
Spain's Jessica Bouzas Maneiro claimed the opening point of the tie with a 6-2, 6-2 win over Sonja Zhiyenbayeva, before world number 79 Yulia Putintseva kept Kazakhstan alive in the contest by defeating Bucsa 6-2, 3-6, 6-1.
Putintseva's victory, her 28th in the competition, saw her equal the record held by Galina Voskoboeva for most BJK Cup matches won by a Kazakh player.
Bucsa had arrived late in Shenzhen after reaching the singles semifinals and winning the doubles title at the WTA tournament in Guadalajara last weekend.
The long trek from Mexico to China may have accounted for her slow start against Putintseva, who played a near-flawless opening set to take the lead in just 33 minutes.
Bucsa dug deep in the second, countering Putintseva's drop shots with her own mix of big-hitting and soft touches to level the match.
But the 35th-ranked Spaniard ran out of gas in the third, as Putintseva swung the momentum back in her favour to clinch the win and take the quarterfinal tie into a deciding doubles showdown.
DOUBLE DUTY FOR BUCSA
The day was not over for Bucsa, who was back on court some 30 minutes later to partner up with Sorribes Tormo in doubles.
As the highest-ranked Spanish player in both singles and doubles, the Moldova-born Bucsa knew her team were relying on her to pull off double duty in Shenzhen, and the 28-year-old did not disappoint, as she sealed the deal alongside Sorribes Tormo to send Spain through to a semifinal meeting with the Czech Republic.
Earlier in the day, Bouzas Maneiro got the Spaniards off to a flying start, easing past Zhiyenbayeva in a mere 62 minutes.
The Spanish world number 93 faced zero break points, broke her opponent four times and won 82 per cent of the points behind her first serve to give her team a 1-0 lead against Kazakhstan.
Zhiyenbayeva, a 20-year-old ranked 384 in the world, was playing just her second-ever match in the BJK Cup, having made her competition debut during Kazakhstan's victory against Canada in the qualifiers earlier this year.
"For me it was a very short match, unfortunately. I wish I could have done better," said a disappointed Zhiyenbayeva.
The action continues on Thursday with the two remaining quarterfinals taking place at the Shenzhen Bay Sports Centre.
Ukraine will face Belgium in the morning tie before defending champions Italy take on hosts China in the evening.