Joao Sousa advanced to his first career ATP tour semi-final by knocking out Dmitry Tursunov 6-4 6-3 at the St Petersburg Open on Friday.
The 89th-ranked Portuguese, who had a 17-20 losing record on the tour before this tournament broke home favourite and fourth seed Tursunov in the eighth game of the second set.
He then closed out the match with a forehand down the line on his second match point.
Sousa will face Guillermo Garcia-Lopes in the last four after the Spaniard defeated eighth-seeded Denis Istomin of Uzbekistan 6-2 6-4.
Earlier, sixth seed Ernests Gulbis needed exactly one hour to book his place in the semi-finals with a comfortable 6-1 6-2 win over Roberto Bautista Agut of Spain.
The Latvian will next face world number 112 Michal Przysiezny of Poland, who reached his first Tour-level semi-final with a 7-6 (9/7) 1-6 6-3 triumph over Czech seventh seed Lukas Rosol.