Top seed Roger Federer fought back to beat Diego Schwartzman in three sets and reach the Istanbul Open final.
Federer, the world number two, received a code violation for angrily hitting the ball away as he dropped the first set against the Argentine eighth seed.
However, the 33-year-old Swiss recovered his poise to win 2-6 6-2 7-5 and close in on his 85th career title.
Third seed Pablo Cuevas of Uruguay beat Bulgarian second seed Grigor Dimitrov 6-2 6-4 in the second semi-final.
"I had a slow start maybe, yesterday was tough so it took me a little bit of time," said Federer, who also needed three sets against Daniel Gimeno-Traver on Friday.
"I am still here, I am hitting the ball well. I am playing against opponents who have nothing to lose. As long as I find a way to win it's great."
In the Czech Republic, home favourite Karolina Pliskova beat compatriot Lucie Hradecka 4-6 7-5 6-3 to win the Prague Open.