Rory McIlroy struggles to make gains in US PGA Championship first round

Rory McIlroy struggled in the early stages of his first round in the 105th US PGA Championship (Eric Gay/AP)

Rory McIlroy was unable to hide his frustration after making a slow start to the 105th US PGA Championship.

Following a delay of almost two hours due to overnight frost, Oak Hill member McIlroy failed to register a birdie as he covered his opening nine holes in three over par.