Tiger Woods said the hours he dedicates to fitness training had paid off as he won his 13th major at the USPGA at Oklahoma's sweltering Southern Hills.
Staying in shape is a huge advantage - at home all the miles I log on the road and run in the heat
The American teed off for his final round in temperatures of 39C (101F).
"Other guys have gotten tired. You see their shoulders slumping and dragging. I feel fine," the 31-year-old said.
"You should always train hard and bust your butt. Not everyone considers golf a sport and they don't treat it as such. You pay the price."
Woods is renowned for changing golf by making hours in the gym mandatory.
"You outwork everybody and days like today it showed," said the world number one.
"When I was walking up 18 I felt the same way I did going off the first tee. Staying in shape is a huge advantage - at home all the miles I log on the road and run in the heat."
This one feels so much more special than the others
Woods held off a charge from American Woody Austin and South Africa Ernie Els to defend his USPGA crown and edge to within five of Jack Nicklaus's record of 18 majors.
"These guys made a run at me but I got it done somehow down the stretch," said Woods.
"This has turned into a great year. I just didn't get it done in the first three majors."
Woods finished second at the Masters and US Open and came 12th at the Open as he contemplated a first year without a major victory since 2004, when he was rebuilding his swing.
Sunday's victory at Southern Hills, by two shots from Austin and three from Els, was the fifth major title in the past 12 tries for Woods, who has won all 13 of his majors when beginning the final round in front.
Woods believes his hours in the gym paid off in the Tulsa heat
Woods says he is a a better player now than he was in 2000, when he won 12 tournaments including the USPGA, Masters and Open, because he has mastered the art of winning.
"You start to get a feel for how to do it," Woods said. "There is an art to winning and I certainly believe that. When I am out there on the course I will reflect back on how I got it done before.
"I have more shots than I did back then. I am more experienced and I have learned how to make adjustments on the fly. I am sure I will say the same things about myself seven years from now."
Woods teed off amid sweltering 39C temperatures (101F) on Sunday and stressed the importance of physical fitness.
"When I was walking up 18 I felt the same way the same way I did going off the first tee," he said. "Staying in shape is a huge advantage. At home all the miles I log on the road and run in the heat.
"You pay the price. You outwork everybody and days like today it showed.
If you would have told me 12 years ago that I would have this many wins and this many majors I would have said 'no way'
Woods insisted this victory was his most satisfying because it was his first major triumph as a new father and both his wife, Elin, and newborn daughter Sam Alexis were in attendance.
"Having Sam and Elin there, it feels a lot more special because my family is here," Woods said. "It used to be my mom and dad. Now Elin and I have our own daughter."
Woods missed the cut for the first time in a major at last year's US Open in the first tournament following the death of his father, Earl, but he followed it with an emotional win in the Open at Hoylake.
"This one feels so much more special than the other majors," he said. "The British Open last year was different but this one felt so right to have Elin and Sam there.
"I was so excited and just wanted to given Elin and Sam a kiss and get back to signing my scorecard."
Woods won his first major at the 1997 Masters and reached 13 majors in just 44 attempts as a professional - nine fewer than Nicklaus.
Nicklaus was 35 - four years older than Woods - when he captured his 13th title at the 1973 US PGA.
"If you would have told me 12 years ago that I would have this many wins and this many majors I would have said 'There is no way'," he said.
"I have exceeded my own expectations and I'm certainly not against that.
"When you first start your career, 18 is just a long way away. And even though I am at 13 it is still a long way away. You can't get it done in one year.
"It is going to take time, as I've said before. It took Jack 20 years to get it done. It is one of those things where it is going to take time.
"Hopefully health permitting and everything goes right and I keep improving that I'll one day surpass that."