McIlroy dedicated the win to his father Gerry who had a double lung transplant at the end of September and has been in a Cleveland hospital since then.
"My dad is a massive part of my life and has been my biggest supporter," said the Northern Irishman who tied the record of Scotland's Colin Montgomerie after a dramatic final round of the season-ending $10 million DP World Tour Championship.
"He is the one that got me into the game and the one that told me to follow my dreams and never give up and never think that you're not good enough.
"It's obviously been difficult. He has been living with this for 18 months, and it got to the point where the last resort was a transplant. Thankfully, the operation was a success and he's recovering well.
"It's been a stressful time for our family. If things were not looking as good as they were, I probably wouldn't have felt comfortable travelling or being too far away.
"I went up to see him before I left for Abu Dhabi a couple of weeks ago, and he said to me, 'Rors, go and win me The Race to Dubai'. That was in my head for the last two weeks, and I really wanted to do it for him."
The tournament itself was a runaway win for England's Hatton (66) even if all eyes were on the fascinating battle between McIlroy and Spain's Chacarra, playing a group behind him.
It all came down to the 18th hole, where McIlroy made a disappointing par to finish on 10-under par, but that was good enough for a solo second place.
That took his ranking points to 5,044.86. Chacarra also could not get a birdie on the final hole and closed with a 69 for a tied third place at eight-under alongside Finland's Oliver Lindell (65).
'A good fight'
The European number one crown was secured with a bogey-free round of five-under par 67. Chacarra's final round featured six birdies but also three bogeys.
"It was a good fight. I just came out short," said Chacarra.
"Obviously, when you play with the best in the world, and he's played here 14, 15 times, you knew it was going to be tough, and he had a better day than I did."
Hatton finally finished with seven birdies against a solitary mistake on the third hole on a day when he again dazzled with brilliant short iron and wedge play.
The win was worth $3 million and he also climbed to third in the Race to Dubai behind McIlroy and Chacarra, his career best finish.
"This is really special. I was really nervous today. I didn't say anything to anyone in my team or even to Emily (wife). I've had a bit of heartbreak around here, and I felt like it was going to be a difficult day," said Hatton, runner-up in the championship in 2016 and 2022 and who has now matched Jon Rahm's record of winning six Rolex Series (DP World Tour's version of elevated events) titles.
"I was just trying to keep my head down and try and make birdies. Just really proud of how I played on the back nine. The putter was amazing and it certainly saved me all week."
Chacarra, Patrick Reed, Casey Jarvis, Jayden Schaper, Daniel Hillier, Jacob Skov Olesen, Lindell, Andy Sullivan, Bernd Wiesberger and Joe Dean secured the 10 PGA Tour cards that were up for grabs based on the Order of Merit positions.
The new season of the DP World Tour starts in two weeks in Australia with the BMW Australian PGA Championship.
