Billy Horschel always has been resourceful with a golf club in his hand. At around age 7, when he hit a ball through the living room window of the family’s central Florida home, did he panic? Did he freeze? No. He blamed it all on his little brother.

These 20 years later, as Horschel approached a round of golf that held all the financial promise of a backyard oil strike, there was room to wonder how he would react. For it is particularly difficult to steady a putter while hyperventilating.

Yet again, he had an answer for the situation, an honest one this time.

“I woke up (Sunday) morning and I just had this sense of calm over me, which is a little bit unusual,” he said. “I was just so calm waking up — wasn’t nervous at all — and I got to the course and felt so relaxed out there.”

Thus, a sometimes excitable golfer was as cool as Bogart on Sunday, posting his 2-under 68 and claiming his three-shot victory in the Tour Championship that came with an $11.4 million payday. That included both the first-place Tour Championship purse money and the $10 million bonus for winning the FedEx Cup points title.

Challenges, they came and went. Playing partner Rory McIlroy was on his bumper for the first five holes. Jim Furyk tied him for about a minute on the back nine before it got to be his nap time. The likes of Justin Rose and Chris Kirk and Jason Day were biting at his ankles. Never did any of that seem to kick Horschel’s heartbeat into overdrive.

Seeing how his son had just found the fairway and how he was so lightly striding to his ball, Billy Horschel Sr. said, “I felt like he had it after his first drive.”

A funny, revealing thing happened on that first hole. McIlroy ripped his first drive as if to make a booming opening statement. A 324-yard launch “that was dumbfounding,” Horschel said. But did he clinch up? Did he begin having self-esteem issues? No. He started joking around with NBC course reporter Roger Maltbie about McIlroy’s absurd length.

He had come to the first tee tied for the lead with the world’s No. 1 at 9 under. A shootout loomed. But McIlroy’s powder, along with his golf ball, got wet on the par 3 sixth. His double bogey there began a woeful six-hole string, in which McIlroy gave back five strokes to par.

“I just got really frustrated and couldn’t muster the energy to try and get something going again,” McIlroy said.

Meanwhile, Horschel was gliding about the front nine at 2 under, threatening to lap the field.

Playing just ahead of him, Furyk temporarily tied for the lead with a birdie on the par-5 15th hole. That required an answer, on a hole that Horschel had somehow failed to birdie the previous three rounds. This time he got up and down from the bunker on 15, canning a 5-foot putt for birdie and sole possession of the lead again.

So what if Horschel’s tee shot on 16 went camping in the woods to the right? So what if that best he could do was punch it back to the fairway? His 30-foot par-saving putt was either going to find the hole or downtown Decatur, it was so rapidly rolling. It chose the hole.

“I heard a roar and I heard someone say, ‘Ice water.’ So I kind of assumed that Billy knocked in the par putt,” Furyk said.

“It was obviously the key to winning, because if that doesn’t happen, you know, it gets a little bit tighter and who knows how it ends?” Horschel said.

Striding up the 18th with a three-stroke lead and his ball safely on the green, Horschel began talking to his caddie Micah Fugitt about dreams. Some are better are others. Horschel said as a kid he dreamed about getting hit in the face with a baseball bat shortly before it happened. And danged if earlier this year he didn’t dream about holding the FedEx Cup.

Sunday was the crescendo of a most masterful month of golf. It was Horschel’s second consecutive victory — and would have been his third had he not botched his final approach at the Deutsche Bank Championship three weeks ago, settling for second.

And yes that is the stuff of dreams when you grow up learning to play on a par-58 muni course that has since been reclaimed by the weeds. Just as it is when your father is still working in home repair, your mother is getting around to graduating from college later this year, your wife is expecting your first child and at no time have you ever been able to take any portion of success for granted.

So, if the former Florida golfer got a little excited at the end and began doing the Gator chomp on the 18th green — “I just wanted them to know that a University of Florida Gator came into Georgia Bulldog country and was able to come out victorious,” Horschel said — please try to understand.