PORTRUSH, Northern Ireland — You cannot hide in golf. No other sport exposes the competitor as cruelly as golf does.

There are no timeouts in golf. There is no halftime break. The coach cannot pull you aside, give you a pep talk or set you straight.

In baseball, if you’re a pitcher and you’re getting rocked like a batting practice tosser, the manager can bring in a reliever.

In football, if you’re a quarterback and you’ve thrown five interceptions in the first half, the coach can put the backup in.

In basketball, if you’ve shot 0-for-20 from the field in the first half, the coach can put someone else in.

In hockey, if you’re a goalie and you’ve let in six goals in a period, the coach can send in the backup.

In golf, there are no subs. You start the game by yourself and you finish it by yourself regardless of how sideways your round has gone. And if it’s going bad — like, real bad — the golf course can be the loneliest place in sports.

It didn’t take long in the first round of the British Open at Royal Portrush on Thursday morning before David Duval looked very lonely.

Birdies on the first two holes had given Duval, the 2001 British Open champion, what turned out to be false hope. Because what followed you wouldn’t wish on your worst golfing enemy.

After pars on Nos. 3 and 4, Duval undid all the good from the 2-under-par start with a quadruple-bogey 8 on the fifth hole. A bogey on No. 6 followed. And then this: Duval took a 14 on the par-5 seventh hole in one of the most bizarre sequences in major championship history.

The 9-over-par score tied for the second-highest score in Open Championship history with D. Murdoch’s 14 at Prestwick’s first hole in 1925. It was one shot short of Herman Tissie’s 15 at Troon’s Postage Stamp in 1950.

“It’s just one of those God-awful nightmare scenarios that happened, and I happened to be on the end of it,’’ Duval said afterward. “I’ve posted 85 twice, but never a 90. It was a long day, rough day.’’

Initially, the official Open leaderboard had displayed an 8 for Duval on the seventh hole. Then it was changed to a 15, and then, when he signed his card after the round, it was posted as a 13. About two hours after his round, tournament officials revised it to a 14 “following an error in reviewing his score.”

Here’s how the R&A described it:

“David Duval’s score on the par-five 7th hole has been adjusted to a 14 instead of a 13. His score for the first round is now 91, 20-over par. The adjustment was made following an error in reviewing his score on the 7th hole. David lost his first two balls from the tee and then played a wrong ball for the third ball played from the tee.

“On discovering the mistake at the green, he had to return to where the wrong ball was played, but the correct ball could not be found. Therefore, he had to play again from the tee for a fourth time under penalty of stroke and distance. He played six shots in completing the hole with the fourth ball from the tee. He incurred a two-shot penalty for playing the wrong ball, but the strokes played with the wrong ball do not count (Rule 6.3c). No further penalty was applied for the score adjustment.’’

Duval, a dignified champion who once held the world No. 1 ranking during the Tiger Woods era (which says a lot about just how good he was in his prime), could have done a lot of things out of frustration and embarrassment — any of which would have tarnished his reputation.

But he didn’t. He carried on.

How?

“I believe in what I do,’’ Duval said.

When the nightmare was over, Duval could have run and hidden, blown off the waiting reporters who wanted to talk to him.

But he didn’t. He stood tall and answered every question with grace.

“You have an obligation as a professional athlete if you play, you post your score,’’ Duval said. “Am I happy about that? Is there some, I don’t know, embarrassment to it? I don’t know. But I teed off in the Open and I shot 90 (91) today, so put it on the board.’’

Duval, clearly shell-shocked more than two hours after that fateful seventh hole, insisted this was “not reflective of anything I have been doing.’’

“I came in here with fairly high hopes,’’ he said. “I had some good practice. I played in Colorado last week, and although my scores weren’t that good, I drove the ball like I used to drive the ball and hit shots like normal. Everything was there.’’

Until it wasn’t.