For months, golf fans wondered whether Jordan Spieth was “back’’ after a long spell during which he struggled with his swing and failed to win.

Spieth ended a drought of nearly four years without a victory earlier this year when he won the Valero Texas Open. Now, after the first round of the British Open, Spieth has positioned himself to win his first major championship since 2017.

He shot a 5-under-par 65 on Thursday at Royal St. George’s and stands one shot out of the lead held by Louis Oosthuizen.

Two omens that may bode well for Spieth: In the previous two major championships when he’s opened with a 65 or better, he won the 2015 Masters and the 2017 British Open, and he’s paired with Branden Grace for the first two rounds. Grace was paired with the last two British Open winners in the first two rounds — Francesco Molinari in 2018 and Shane Lowry in 2019.

“I think that’s coincidence,’’ Spieth said. “[But] if it happens four or five times in a row, maybe people start paying off to see who can get paired with him the first two rounds.’’

Spieth looks and appears at home in British Opens. He finished tied for fourth in 2015, won in 2017, was tied for ninth in 2018 and tied for 20th in 2019.

“I’ve really loved this tournament,’’ he said. “I’ve played well here, whether I’ve come in in form or not. [Links golf] brings a lot of the feel aspect into the game. I think I shorten swings up over here and hit more punch shots and just stuff that I probably should be doing at home.

“You get less swing-focused and more shot-focused over here because the second you take your brain off of what you’re hitting, you may not find your ball. There’s always some shot you have to play that gives you a little bit of an advantage or certain club selections based on you hit a fade or a draw. I guess to sum that up, there’s a lot of external factors over here, and I think that external is where I need to be living.’’

In other words, Spieth finds himself not thinking too much and getting into his own head at British Opens.

“Golf is a game played between the ears, right?’’ Spieth said. “When it’s not going great, you can certainly lose quite a bit of confidence in it. [The slump] was the first time I’ve had to really try and build confidence back up, and it takes time.

“By no means do I feel like I’m where I want to be mechanically yet, but this year has been a really, really good progression for me, and that’s all I’m trying to do is just get a little bit better each day.’’

Interestingly, even when Spieth was struggling the past few years, he had some good moments in majors when he was in contention (third at the 2018 Masters and 2019 PGA).

“I look back and I had a chance to win at least one of the majors each year when I felt like I had no idea where the ball was going,’’ he said. “I feel like I’ve been trending the right way and certainly had a chance this year already at Augusta (a tie for third). I like where I’m at.’’

Asked if he thinks success will feel differently with another British Open win than it did when he had it earlier in his career pre-slump, Spieth said, “I’m not sure. I would hope to answer that question for you in a few days.’’