Houston - Fernando Verdasco booked his first ATP semi-final of 2014 on Friday, powering home to beat Donald Young 7-6 (7/1), 6-1 in the US Men's Clay Court Championship.
The fourth-seeded Spanish veteran admitted Young's solid play had him feeling "uncomfortable" in the opening set, but once he'd pocketed the tiebreaker he was on his way.
"He played great tennis in the first set," Verdasco said. "I kept fighting and he didn't serve well in the game I broke him. After that he started missing a little more, including in the tie-break. After I won the tie-break I took extra confidence and started to be more stable on the court."
Verdasco next faces Santiago Giraldo, who defeated Alejandro Gonzalez 6-3, 6-4 in an all-Colombian clash.
The 26-year-old Giraldo will be playing the fifth ATP semi-final of his career and his second in 2014. He fell to Leonardo Mayer in the semis at Vina del Mar earlier this year.
Third-seeded Spaniard Nicolas Almagro also advanced, downing American Jack Sock 6-2, 6-4.
Almagro will face American Sam Querrey, who fired 15 aces and saved all four break-points he faced in a 6-3, 6-7 (8/10), 6-3, victory over Germany's Dustin Brown.
Querrey, a former world number 17, is in the final four in Houston for the second time. He finished runner-up in 2010.
"You have to be ready for anything," Querrey said of Brown's varied game. "He might come in, he might stay back, he might serve and volley, slice a forehand, drop shot. You have to expect everything and not get frustrated when he wins points."
Almagro will be trying to improve on his runner-up finish in Houston last year, when he lost to American John Isner in the final.
Results from the ATP Tour's US Clay Court Championship on Friday (x denotes seeding):
Sam Querrey (USA) bt Dustin Brown (GER) 6-3, 6-7 (8/10), 6-3
Nicolas Almagro (ESP x3) bt Jack Sock (USA) 6-2, 6-4
Fernando Verdasco (ESP x4) bt Donald Young (USA) 7-6 (7/1), 6-1
Santiago Giraldo (COL) bt Alejandro Gonzalez (COL) 6-3, 6-4