Halep has never lifted the title in Cincinnati, her previous best coming in 2015 when she was runner-up to Serena Williams, but if she manages the feat she will become the new world No.1.
Spaniard Muguruza, who had failed to capture a title for more than a year following her triumph at last year's French Open, was now celebrating winning two trophies in as many months as she backed up her Wimbledon victory with her glorious run in Cincinnati. "I was thinking about it".
"The U.S. Open is a very long tournament", said the tall 23-year-old.
Kyrgios, who bounced top-seeded Rafael Nadal out of the tournament in the quarterfinals, could not rely on his decisive serve for the win, although he did fire 15 aces to Dimitrov's six, he also had four double faults to the Bulgarian's five. Halep would start to show signs of turning things around in the next game as she pushed Muguruza to deuce for the first time in the match, but the Spaniard still held. "It takes some time to get over that". I'm just happy obviously with the win, but I'm just happy with the way I kept myself together throughout the whole match.
"It's been great to see you back in top form, I always knew you had it in you".
However, Muguruza, who is ranked No. 6, did not have her serve broken the entire match.
"I was struggling a couple of weeks ago and Grigor got me out on the practice court", Kyrgios said after warmly hugging his conqueror at the net. On the 14th point of the game, Muguruza broke through and controlled the rest of the set. "I didn't have chance in the second tiebreak".
Muguruza took charge early, breaking Pliskova in the first and last games of the first set.
To reach the coveted top ranking and win the W&S Open for the first time, Halep must successfully navigate the challenges Muguruza presents.
"I played so bad today and Garbine played so well", Halep said on court at the end. Obviously, a tough schedule for me the last two days - three matches in about not even 24 hours. "I don't really know what I had to do, and I think she was just too good today".
"But I think that was just the key to be very focused and just composed throughout the whole time of the match".
"The match felt quite tough, it was not easy at all", Halep said.
The Australian who was playing, as Dimitrov, his first final of a Masters 1000, however, was offered the first ball of breakage of the encounter in the fifth game, but was not benefited.
"The difference was he was a lot more decisive at the big moments", Isner said. "It's been a good week for me with [a] few good matches", she wrote.
"Tomorrow is going to be a step forward for me", Dimitrov said.