The Top 2 seeds are through to the semi-finals of the SAP Open in San Jose, with top seed Andy Roddick and No. 2 Fernando Verdasco both posting tight, two-set victories. Denis Istomin is also through to his first-ever tour-level semi-final.

Three-time former champion Roddick had his hands full with Tomas Berdych for the second time this season. Having beaten the Czech en route to the Brisbane International title last month, No. 7-ranked Roddick needed two tie-breaks to defeat the No. 5 seed on Friday, 7-6(5), 7-6(5).

"It's tough - he hits the ball so hard and flat," Roddick said of Berdych. "It keeps you a little bit off-balance. A lot of the time you feel like you're just scrapping and clawing and trying to hang on in some points.

"He forced me to play well tonight. I thought he played a good match - his percentages were great on his first serve and he was hitting the ball well from the baseline. I was fortunate to get through that in two [sets]."

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Roddick has now reached the San Jose semi-finals or better in each of the past seven years, and eight times overall (31-5 at the event). The 27 year old next plays No. 7 seed Sam Querrey, who defeated fellow American Michael Russell, 6-4, 6-3 in the last quarter-final on Friday evening.

Querrey served nine aces and won 80 per cent of points on his first serve in the 66-minute victory.

No. 2 seed Fernando Verdasco scored a 6-3, 7-6(5) win over Lithuanian newcomer Ricardas Berankis to reach his first semi-final of the season.

No. 255-ranked Berankis, aged 19 and the first man from his country to reach an ATP World Tour singles semi-final, put up a great fight against the 11th-ranked Verdasco. Despite not giving the Spaniard a single break point opportunity in the second set, Berankis was unable to force a deciding set as Verdasco's experience paid dividends in the second-set tie-break.

"I think I served well," said Verdasco, who defeated Benjamin Becker in the second round on Thursday. "I think overall I didn't play as well as yesterday, but my serve helped me out in many points during the match because some times he was more solid than me from the baseline.

"I never saw [Berankis] play before today, and what I saw he's very good. He serves well, and from the baseline has a good forehand and backhand - I didn't see any big weaknesses."

Verdasco now meets unseeded Uzbek Denis Istomin, who will be making his own personal history on Saturday as he competes in his first tour-level semi-final.

World No. 96 Istomin, who defeated American rising star Ryan Harrison and No. 4 seed Tommy Haas en route to the quarter-finals, overcame a mid-match lapse to oust German No. 6 seed Philipp Kohlschreiber, 6-1, 1-6, 6-3 in one hour, 37 minutes.

"I'm so happy - the first time in my career I play a semi-final," said Istomin, the first Uzbek man to rank in the ATP World Tour's Top 100. "Today I played so well - I think it's the best match I played of my life."

This will be the first meeting between Verdasco and Istomin.