"When I had my (final) putt, I marked it and turned around and just happened to see my parents, saw my grandma and grandpa, and I just got a huge knot in my throat and had to put my head down".
Thomas will go down as the last victor of the WGC-Bridgestone Invitational.
I said, I don't know why, or its really been that long or what, but I'm nervous today.
McIlroy made up three shots in the final round in 2014 when he rallied to beat Sergio Garcia at Firestone.
Thomas's round seesawed between six birdies and three bogeys but was good enough to allow him to enjoy a true advantage over pair of players tied for second place - Northern Ireland's Rory McIlroy (who shot a 67) and second-round co-leader Ian Poulter (70) of England on a day when scoring was at a premium on the demanding South Course.
The victor had nine points in the round and 47 overall under the format that awards eight points for albatross, five for eagle, two for birdie and zero for par, and subtracts a point for bogey and three for double bogey or worse.
The course started to get a little firmer. At the Bridgestone Invitational, he became the 21st player to win a World Golf Championship and a major.
Sunday at Firestone will be the eighth time this year they play together in a tournament, and the number grows next week when they play the opening two rounds with Tiger Woods at the PGA Championship.
"The first 10 holes were pretty good", said Johnson.
Thomas could not have asked for a better week.
"I take a lot of pride in how I played today", Thomas told reporters.
Spieth made a run at completing the career grand slam in just one year in 2015, when he won the Masters and U.S. Open before finishing T4 at The Open Championship and second in the PGA Championship.
Winning the WGC-Bridgestone Invitational on Sunday had put Justin Thomas in a "great place mentally", with the timing ideal as he gears up to defend the PGA Championship title.
Firestone has held tour events since the Rubber City Open in 1954.
Straka earned $121,500 to jump from 130th to 29th on the money list with $145,000, with two events left to get into the top 25 and earn a PGA Tour card. In many respects, it was the precursor to the World Golf Championships by bringing in winners from around the world.
Bridgestone shifted its title sponsorship to the PGA Tour Champions, which will bring its Senior Players Championship to Firestone next year. The World Golf Championship instead will move to Memphis, Tennessee. Stanley closed with a 68. Not to worry. He shot 73 and tied for sixth.
He said earlier this week that it "feels like I haven't won in forever".
"It's really cool", Thomas said.
Cook falls but England reach 83-1 v India at lunch
MORNING SESSION: England were only able to add two more runs to their overnight score. India lost its third wicket on 59 in the form of Shikhar Dhawan who scored 26.