Second-seeded South African Kevin Anderson powered into the semi-finals of the US Open tune-up tournament at Winston-Salem on Thursday with 6-2, 7-6 (7/1) win over Borna Coric.
Anderson improved to 6-0 in quarter-final matches in 2015, firing 10 aces and never facing a break point in the 82-minute triumph.
He took full advantage of the 18-year-old Croatian`s errors in the opening set, when Coric coughed up five double faults and won just three of 11 possible points on his second serve.
In Friday`s semi-finals Anderson will play unseeded Tunisian Malek Jaziri, who upset sixth-seeded Brazilian Thomaz Bellucci 6-3, 6-2.
American Steve Johnson reached the final four without lifting a racquet as Lu Yen-Hsun of Taiwan withdrew from their quarter-final with a back injury sustained in a three-set win over South Korea`s Chung Hyeon.
"It happened at the end of the match yesterday," Lu said. "There is some inflammation in a disk, which causes the muscles to tighten up. It`s difficult for me to extend my body, especially backwards."
Johnson, bidding to reach his first career final on the ATP Tour, will face French qualifier Pierre-Hugues Herbert, who needed one hour and 57 minutes to overcome Spaniard Pablo Carreno-Busta 4-6, 7-6 (7/5), 6-2.
Carreno-Busta, who had 11 aces and just one double fault, served for the match at 5-4 in the second set, but Herbert hung on to force the third set, breaking the Spaniard twice in the final frame to seal the win.