"I am truly happy and can not believe what I have achieved, " she said after her win over Caroline Wozniacki yesterday.
"Still, I think I'm able to play better tennis", Pliskova said, "which, probably, I'm going to need" against Halep.
Bacsinszky had to break for treatment during that first set after injuring her knee.
In comparison, Saturday's duel promises to pit the would-be world No. 1 against a foe of much smaller stature, a new test for the veteran seeking her maiden major victory in France. "I take on a young player, it will be an interesting challenge".
Coming into Thursday, Halep led Pliskova 4-1 head-to-head and upped that mark to 5-1 lifetime with the victory.
Ostapenko is the first lady tennis player from Latvia to advance to the semis of a Grand Slam tennis tournament. She fended off another set point in the next game but a forehand error handed Halep the set.
Bacsinszky won the last four games to wrap up the second set 6-3.
Halep is the only break he took the first set, the second set Pliskova has already scored once at the reception, and in the next game played three break points and leveled the score in sets. Despite finishing the set strong and taking that momentum into the second set, Pliskova began to sputter in the third set.
The 5-foot-6 (1.68-meter) Halep is a ball-chasing, defensive dynamo unafraid of lengthy exchanges who gets to almost everything off an opponent's racket and is careful when she swings.
A few hours later Evert had her answer as Ostapenko, the youngest, lowest-ranked and least experienced of the quartet, produced a fearless performance to beat Bacsinszky 7-6 (7-4), 3-6, 6-3, belting 50 winners in the process. Of course she has nothing to lose. That means a loss in the final would give her one more shot as a favorite at a Slam over the next seven-plus months, which might feel like an eternity, depending on a host of factors.
It was an impressive recovery in stifling 28 degree heat, but wasn't enough to encourage the large number of fans who had abandoned their seats on Philippe Chatrier court to return. "I have the mentality to win, but it's going to be tough", said Halep, who lost to Maria Sharapova in three sets in the 2014 French Open final. And in 2013, Bartoli was 15th when she beat Sabine Lisicki, who was 23rd; that marked only the second time in the Open era that two women without a Grand Slam trophy met for the Wimbledon championship.
"She came out like a thunderstorm in the third set". Myskina's opponent - another Russian, Elena Dementieva - made it the first French Open final since 1981 with two participants making their debuts in a Grand Slam title match. Ostapenko's aggressive style will clash against Halep's formidable deep game, and the match may come down to who ends up blinking first and has to adapt their respective styles.