Rory McIlroy is hoping he can break out of a slump in form with a strong showing at this week's US PGA Championship.

Last week's T68 finish at the WGC-Bridgestone Invitational in Akron, Ohio, was the 20-year-olds worst finish of the year but McIlroy insisted he had not run out of steam as he prepared for the last major of the year at Hazeltine National.

"I don't think it's tiredness. I was speaking to a few people about it last night and in golf you're always going to have a few lulls, and then you're going to have obviously the highs, as well," McIlroy said.

"It's just about making the most of playing badly; not playing badly but not playing your best.

"Turning the 40ths, 50th-place finishes into top-30s or top-20s. I'm still learning how to do that."

McIlroy said being a mid-division player in the big tournaments held no interest for him but he was optimistic things would turn around at Hazeltine National this week.

"It's hard for me to go out in a major going out in 50th position and trying to get myself up for it and trying to finish as high as possible because the juices are not really flowing.

"It's hard to, you're not really in the tournament, and obviously you want to finish as best you can, but it's hard to whenever you're teeing third or fourth off in the last round.

"But you know, hopefully this week I can play a bit better the first three days and get myself into position in this tournament where I at least have a chance to contend."