"I just wasn't very on with the driver, and I was playing a fade and just kind of got it there early", said Spieth, who could only chip sideways through the trees back to the fairway before missing the green with his approach, adding: "But it was a attractive chip shot (from greenside), probably couldn't have gotten closer with a whole bucket of balls".
"Today I felt the Sunday-type pressure of leading the Masters on the middle of that back nine, and adjusted extremely well".
"It's Round 1", he said.
"So, I imagine there will be plenty of times, if not from, you know, early on tomorrow that I don't lead this tournament anymore". "It's about riding momentum from last week and this round".
That bullish assessment came before Spieth caught fire, stringing together five birdies on the back nine as he seized a two-stroke lead over fellow Americans Matt Kuchar and Tony Finau.
Rory McIlroy, who needs a win this week to complete a career grand slam, was in good form, firing a 69 to sit one shot further back at three under alongside Henrik Stenson, Adam Hadwin, Charley Hoffman, Patrick Reed, Rafa Cabrera Bello and China's Haotong Li.
Saving par on the final three holes in the opening round Thursday helped him keep it in sight.
In the trees off the 18th tee, he could only punch out to the fairway. It was Woods' first competitive birdie at the famed course since April 12, 2015, when he carded a 4 at No. 15 in the final round of the Masters.
"This golf course specifically, brings out a lot of feel in my game, and I think that's advantageous", he said. "I was looking forward to grinding it out and I made a little comeback on the back nine to get myself back into this tournament".
"It's nice that I was able to shoot a score like this", he said. So, basically, he played the 15th hole in 8-over and the other 17 in 1-over.
Woods turned 42 at the end of a year ago.
"The nerves really were simply normal". I wasn't flying high.
"I was pretty sure they weren't feeling anticipation about me", quipped Tommy Fleetwood, who joined Woods in a threesome that also included Marc Leishman. "I was very confident in what I was doing".
Garcia added: "I felt like I hit a lot of good shots and unfortunately the ball just didn't want to stop". After another errant drive on the par-5 13th, Woods hit another low shot that scattered the patrons, he pitched to 16 feet and narrowly missed a birdie attempt.
Sergio Garcia's hopes of a second straight title went up in smoke - really more like down the slope - at the 15th hole. The previous high score on the hole was an 11.
That was more than the defending champion Sergio García could say after a meltdown on the par-5 15th cost him any realistic chance of surviving the cut.
The 28-year-old world number 34 made six birdies and holed from 13 feet for a par at the last.
Tony Finau didn't appear the least bit hampered by his ailing ankle while carding a 4-under 68 in Thursday's opening round of the Masters.
"I don't know", Garcia said, trying to find the words in his non-native language.
Finau was cleared to play after receiving an MRI exam on his dislocated left ankle Thursday morning. I don't do well in domes or driving ranges.
Finau said after his round that his pain rated a "10 out of 10" when the injury happened, but it bothered him less and less as Thursday unfolded.
Only two players have come back from seven shots behind after the opening round to capture the green jacket.