Washington - Top seed Mardy Fish reached his first semi-final of the season with a 6-3, 6-4 defeat of Belgian Xavier Malisse in a battle of veterans at the joint ATP/WTA event here on Friday.
The American has only been playing a month since recovering from a heart-scare with his irregular beat which was repaired through a medical procedure in May.
The world No 15, who broke through into the ATP top 10 in 2011 before sliding out, will play against good friend and fourth seed Tommy Haas after the 34-year-old German crushed compatriot Tobias Kamke 6-1, 6-2 in 66 minutes.
Second seed Alexandr Dolgopolov beat 2002 winner James Blake 7-6 (7/3), 6-4 after trailing 4-1 in their match, setting up a semi with last week's Los Angeles winner Sam Querrey, after the eighth seed beat his South African doubles partner Kevin Anderson 6-4, 6-4.
In the women's field, the final will be played on Saturday between Russian top seed Anastasia Pavlyuchenkova and Slovak Magdalena Rybarikova.
Pavlyuchenkova defeated American Vania King, the fourth seed, 4-6, 7-5, 6-4, while Rybarikova put out Sloane Stephens of the US 6-3, 6-3.
Fish will be playing in his first Washington semi after improving to 3-1 over Malisse, whom he last played six years ago.
"This is a nice first for me in Washington," said Fish, who finished with 10 aces. "It's good to go further than normal. I'm very comfortable here and the fast court suits my game. I also appreciate the hot weather."
"I noticed that Xavier seemed injured, he didn't move as well as usual," said Fish.
"I tried to exploit that and may have had more errors than usual, but it worked."
Fish and Haas have not played since 2007, with the American standing 1-2 against the German.
"It will be a good match-up, very tough," said Fish. "As we'll surely play in the day, the weather may be a factor.
"He's had good results recently and is playing some of his best tennis in a long time. He also has some of the most beautiful strokes you will ever see."
Haas, who has moved from outside the top 200 to 36th, finished his rout over No 107 Kamke with four aces and never faced a break point on his own serve.
He now stands 22-9 on the season, 18 months after hip surgery and is looking to win his 14th career title.