Jon Rahm said "everything was difficult" on day two at the US PGA Championship, but matters could hardly have been more different for Justin Thomas.

Rahm, one of the pre-tournament favourites, endured a difficult opening round at Southern Hills Country Club but the Spaniard responded with a respectable, one under par 69 on Friday.

That leaves the world number two on two over par, which should just see him sneak over the cut line. Former world number one Dustin Johnson, meanwhile, is unlikely to be so fortunate, having carded a second successive 73.

Rahm conceded that he has found it tough going so far, though he was nevertheless happy with his second round.

"I can't say I played bad. I gave myself a lot of chances," said Rahm, who balanced out two bogeys with three birdies.

"I think the main thing yesterday was a couple of mistakes, just mental mistakes. There was three; one on eight, skulling that chip. Should have made something better than a six on 13 with a five-iron in my hands. And putting it on dry land on 17.

"Those are three shots that I could have done better and I could be at one under right now, and that was just strictly mental.

"Today I can't ask much more of myself. It was a good day, it was good golf. Just tough. And I played really good to show one under."

One player thriving in the tough conditions in Oklahoma is Thomas, who took the lead off Rory McIlroy with another round of 67, replicating his score from Thursday.

Thomas' sole major triumph so far came at the US PGA Championship in 2017, and the American looks well-placed to push on after heading into the clubhouse on six under through his two rounds, putting the pressure right back on overnight leader McIlroy, who bogeyed his second hole on Friday to drop two shots off the new leader.

"Very pleased. I felt I played, although I played solid yesterday, I played really, really well today," said Thomas.

"The conditions were obviously very difficult. I stayed very patient, tried to get in my own little world and get in a zone and just tried to execute each shot the best I could.

"I felt we did a great job of that and am glad to have a good round to show for it."

Thomas only slipped up once, on the 14th, but made four birdies, but the 29-year-old is wary not to get ahead of himself.

"I like this golf course. I feel like I'm playing well," he continued. "We're halfway through so it's still a long way from home, but I'm very, very pleased with where everything is at and the frame of mind and state of mind that I'm in.

"Just need to try to maintain that the best that I can and keep trying to play good golf."