Jon Rahm has now played 23 career rounds in PGA Championships. Only once before had he endured a day like Thursday.

Rahm fired a 6-over 76 in the opening round at Oak Hill Country Club to match his worst career PGA Championship score, tying the 6-over 76 that he carded in last year's third round at Southern Hills, where Rahm ultimately tied for 48th.

The day actually started well, as Rahm birdied his opening hole, the par-4 10th. He followed with five straight pars before the mistakes began. Rahm bogeyed five of his next six holes. Rahm capped his round with a bogey-double-birdie-par stretch.

"The main thing on this course is hitting the fairway," Rahm explained afterward. "If you put the ball in the fairway you can actually give yourself a lot of good chances. Even 18 today was playing downwind, so if you put it on the fairway, you can have a good look at maybe hitting it close and that's what I didn't do. Obviously the first six holes of the day I played really good. Put myself in a good spot and after that I found myself battling. Couldn't find the fairway and the fairways that I missed cost me bogeys.

"The only thing I can look back on myself is the three short putts I missed on the back nine, I'm between 3 to 5 feet, if I make those putts, I shoot 3 over, which is not the worst-case scenario."

He ranked outside the top 100 in the field in strokes gained approach and putting at the time his round ended. He also was in the negative in strokes gained off the tee.

"It wasn't my best swings on the last two holes and made a birdie and a par," Rahm added, "so there's many ways to do this. You don't need to play perfect."

For his PGA career, Rahm has just two top-10s in six appearances. But there's still hope for this week, Rahm says.

"If I can somehow manage to put a low one tomorrow," Rahm said, "and find myself close to even par going into Sunday, I think I'll have a decent chance."