And then he almost lost it. His grandmother is one of his biggest supporters who navigated her way around the hills of Firestone using a walker in 90-degree heat.
The World Golf Championships in Akron has a yearly economic impact of more than $21 million according to Firestone's website.
This is only the fourth time he has been five shots or closer going into the weekend this year, but there are plenty of others around him. "To make that putt on 1 and again on 2 just kind of calmed me and got me going for the day". "So it was pretty cool to get it done".
Tiger Woods, an eight-time victor at Firestone, started 11 shots behind and figured he would go out with a bang by playing aggressively.
American Justin Thomas prepared for his defence of the US PGA Championship title with a four-shot victory at the WGC-Bridgestone Invitational in Ohio. McIlroy finished the front nine with consecutive bogeys and never recovered.
Tiger Woods had earlier struggled to a closing 73 which contained six birdies, five bogeys and two double bogeys in the space of three holes on the back nine.
Tiger Woods reacts after missing a putt on the 17th hole during the second round of the Bridgestone Invitational on Friday.
Still, this is the first time since the 2015 Wyndham Championship that Woods has started a tournament with two rounds in the 60s, and it is the second-best he has been in any tournament this year through 36 holes; he was tied for second at the Valspar Championship.More news: Huge Indonesia quake rocks Lombok island
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"We sat down and just said, what are we doing wrong?" "But it is what it is, and on to next week".
All he needs to do is ask his good buddy, Jordan Spieth, what it's been like this year. Winless the last five months without feeling as though his game were in disarray, he got the result he needed ahead of the final major of the year.
And so while Spieth heads to Bellerive trying to complete the career Grand Slam, it is Thomas who takes a good bit of momentum, now having won three times this season to join No. 1-ranked Dustin Johnson and Bubba Watson as the only players to win that often.
He lost to Phil Mickelson in a playoff at the WGC-Mexico Championship in March.
Day battled mistakes during the third round at the hard Firestone Country Club but managed to stay near the top of the leaderboard at 10-under-par after a one-under 69 on Saturday. "This is one of the most toughest courses in the entire country", said Ken Wilmoth from North Canton.
His grandparents were both in attendance, and Thomas clearly wanted to win with them there.
So ended a finale at Firestone that otherwise lacked drama.
Thomas had not had a score better than 67, and he had not finished higher than a tie for 28th in his two previous appearances at Firestone.