Arruabarrena was down a break in both sets but came back each time en route to a 64 76(3) victory over the 2013 Bogotá runner-up that was an upset on paper, but was hardly a surprise considering the Spaniard has now won three straight in the head-to-head.
"It was very tough," Arruabarrena said. "She plays very well and we had played several times before, so we know each other well. I played well. At the end of the match I was a little bit nervous, but I got through it."
Including three qualifying wins this year, Arruabarrena is now 12-1 in Bogotá, with three of her four best outings at WTA events having come here - the title in 2012, a quarterfinal showing in 2013 and at least a quarterfinal appearance this year.
Arruabarrena's quarterfinal foe, No.1 seed Jelena Jankovic, also has an impressive history here. The defending champion improved to 7-0 in Bogotá with a 64 63 defeat of Sofia Shapatava.
"I played much better today," Jankovic said. "The conditions are tough here but I'm happy that I improved from yesterday. Hopefully, I will play even better tomorrow."
Also set to face off in the quarters are fifth-seeded Caroline Garcia and Romina Oprandi. Garcia lost four more points than she won but held off Danka Kovinic, 26 63 64. Oprandi was a 64 61 winner over Irina-Camelia Begu to make her first WTA quarterfinal since Brussels last May.
Friday's other two quarterfinals will see No.6 seed Vania King take on 2010 Bogotá champ Mariana Duque-Mariño, and No.8 seed and 2006 and 2011 Bogotá champ Lourdes Domínguez Lino square off with Chanelle Scheepers.
In the doubles semifinals, top-seeded King and Scheepers will play fourth-seeded Sharon Fichman and Alexandra Panova, and second-seeded Domínguez Lino and Arantxa Parra Santonja will face off with Arruabarrena and Garcia.