Padraig Harrington saw his US PGA Championship defence implode on the eighth hole at Hazeltine National - but the three-time major winner insisted he was on the right path to becoming a better player.

The Irishman's quintuple-bogey at the par-three eighth removed him from contention when he was vying for the lead with Tiger Woods and YE Yang.

"Obviously it was disappointing for me," said Harrington, who carded a six-over-par 78 to finish in a tie for 10th place at level par, eight shots behind new champion Yang. "I still made the shots out there. I only got out of position (on) one hole. The few putts I dropped, it could have been a nice number."

Having struggled to get good results all year as he modified his swing in the wake of back-to-back major victories at last year's Open and US PGA, Harrington could at least take heart from his overall performance.

"The positive is I was very comfortable out there and I know that my game is going to get better," he said.