Sloane Stephens and Madison Keys ensured there will be an American in this year's French Open final.
The two great friends, who met in the US Open final last year — won by Stephens – will face each other in the last four at Roland Garros.
Stephens brushed aside young Russian Daria Kasatkina while Keys also went through in straight sets against Yulia Putintseva of Kazakhstan.
Theirs is supposedly the friendliest rivalry in tennis, and Stephens said: “It’s the same thing as always. When we get on the court, it’s time to compete. But before that, we are not going to be weird and awkward.
“Now I just have to go find her, because I need to tell her some juicy stuff. I just went and searched for her in the training room.
“I think everything will be normal. And then when we get on the court, it’s time to compete. It’s go time. Until then, we’re the same girls as always.”
Stephens was in control after winning a marathon game on Kasatkina’s serve for 5-3 before taking the opening set.
She broke again early in the second set and went on to win the next five games for a 6-3 6-1 triumph.
Keys needed a tie-break to take the first set, with her power and accuracy eventually too much for Putintseva during a brutal set point.
She then broke in the seventh game of the second set before going on to win 7-6 (7/5) 6-4.
“I obviously lost to Sloane at the US Open,” said Keys. “But, you know, I feel like on clay it’s a little bit of a different match-up.”
Keys vowed to carry on smiling after moving closer to a maiden grand slam title.
She added: “I have actually been told quite often that I’ll never win or do well because I’m too nice a person and I just don’t have it.
“I think that’s a load of crap, but, you know, it’s just me.
“I don’t think you have to be mean in order to win matches. I think there’s a difference between being intense and wanting it and fighting and just not being nice, so that’s something that I have always stayed true to.
“I’m not ever going to try to be a person that isn’t nice, so that feels more authentic to me and, you know, I think I’m still doing okay. Well, trying to be as nice as possible.”