Rory McIlroy believes his share of eighth place in the US PGA Championship marked a "very big" step in the right direction in a disappointing season by his high standards.

McIlroy's hopes of successfully defending his title effectively disappeared with a triple-bogey seven on the fifth, but the former world number one battled back to record a closing 70 at Oak Hill.

The 24-year-old has still posted just one top-three finish this season compared to five wins around the world in 2012, but was pleased with his performance after making four birdies in six holes towards the end of his second round to simply make the cut.

"I played the best golf of the week today," said McIlroy, who finished three under par, seven behind champion Jason Dufner. "I hit some really good drives and really good iron shots. Didn't quite putt as well as I did the first three days, but really, really happy with my game going into the next few weeks.

"It's a very big step in the right direction. I saw a lot of great signs out there today. Hopefully I can just bring that through to the next few weeks and have a strong finish to the season.

"It's a very big step in the right direction." - McIlroy

"I made a big number on five (although) I hit a good shot, exactly what I wanted to do with it. It just pitched in the exact wrong place. Everything else feels pretty good."

McIlroy finished one shot ahead of compatriot Graeme McDowell, who closed with a 66.