Bertens jumped out early in the first, but Stephens held an early lead in the second before Bertens leveled and eventually took the match.
"For me, I just wanted to grow comfortable on clay and I think I have".
That she also had two wins from three meetings over Halep gave still more weight to her challenge of reaching the final, the most recent of them a three-set thriller in Dubai. Erroneous tennis from Halep's side effaces her previous break as Kiki Bertens was back on serve by avenging for her break.More news: What Trump's trade war with China means for American consumers
"I am sorry to announce that I must withdraw from today's match". Kiki Bertens got a free point as her wide overhead smash directly hit Halep's knee, which consequently took away double break chances from Halep.
"I feel unbelievable of course, it's great to be in the final and I'm happy to finish it in two (sets)", said Bertens.
Bertens came back from 4-2 down in the first set against French Open champion Halep by winning the next three games, striking the first blow in a gripping final full of drama which lasted one hour and 27 minutes.
"So she, I would say, she tried to step a little bit more in the court and I think that's when she plays at her best, but, yes, sometimes it is tough, like. I didn't want to lose twice in a row", said Osaka, who was also defeated by Bencic at Indian Wells in March.More news: Detective Pikachu earns $58 million domestic for opening weekend, Certified Fresh
"In the third I just started over again, I played smarter, opening up the court and being more aggressive".
"I think I played wrong, and I'm upset about that".
Halep, though, was not backing off from her strategy, broke straight back, and they would continue like the proverbial unstoppable force versus immovable object in a wonderful passage of play and high intensity. The Swiss opened with a fine touch volley victor, and she edged to 3-0 with a backhand return-of-serve victor.
Bertens joined the WTA Insider Podcast after her Madrid win to reflect on her blistering week in the Spanish capital, the lessons she's learned as she's ascended into the WTA Elite, and how she hopes to cope with the spotlight now that she's become one to beat.More news: Mariana Trench: Deepest-ever sub dive finds plastic bag
"It's going to be really tough (against Halep), we played each other in the past so I know it will be a tough battle, but I'm ready for it, one more push here".