After establishing herself as an American tennis star by winning the 2017 U.S. Open, Stephens looked - at least for the first hour of the match - in command and on her way to becoming a more prominent, respected force in women's tennis. Plus, now that she has a Grand Slam win at her back, you can not predict Halep to be the outright victor just yet.
But it was the German who started the stronger, out-hitting her rival with lethal accuracy, to win the first four games as Halep struggled to find her serving rhythm and peppered the tramlines with unforced errors. In the last game I felt I could not breathe any more.
"So I don't have any negative feelings towards her, which again, was a little disappointing to see in that hearsay book", Williams added. Halep has been on the cusp of winning Slams before, but she has cracked mentally on every occasion, losing all three of her finals in three sets.
Stephens started the game aggressively but Halep was able to hold her own to start with.
Halep has won five of her past nine matches against the 12th-seeded Kerber, including their most recent encounter in the Australian Open semifinals when she saved two match points.
Stevens netted a service return to bow out.
In her other grand slam final, in Paris in 2014, the 26-year-old lost a three-set battle to Maria Sharapova. At the Miami Open in March, she won the title, beating four major champions in a row.
This time previous year, Stephens was still sidelined with a foot injury that her walking around in crutches and Keys was coming off a second wrist surgery.
Halep said afterewards: 'In the last game I felt that I could not grip [the racket] any more, so I just tried not to repeat the past year. She's a great opponent, a great player. This much is certain: Simona Halep is a Grand Slam champion, now and forever.
Stephens briefly looked out on her feet, but raised her game by shortening the points to break straight back before levelling the set at 4-4, helped by the first ace of the match.
After breaking Stephens to even the match at one set apiece, she jumped out to a 5-0 lead in the final set. So if any of you want to tweet that, I would be very happy, give you guys a like, a retweet or something.
Amid some spellbinding rallies, Stephens clinched a solitary break to take the first set.
Halep is the bookies' favourite to finally win a first Grand Slam and leads 5-2 in her head-to-head record against Stephens.
"I lost three times until now and no one died", Halep said, "so it will be OK".
After Saturday, Halep joined Martina Navratilova (1978 Wimbledon) and Jelena Ostapenko (2017 French Open) as the only women in the Open era to win their first major title after coming from a set down to win in the title match.
When the match ended, Halep dropped her racket at the baseline and covered her face with her hands.