Rory McIlroy can't seem to perform in front of a home crowd.

The Northern Ireland star looked bewildered as he shot a 9-over-par 80 — his worst score of the season — in Thursday's opening round of the Irish Open. He finished the morning at the bottom of the leaderboard, with half the field yet to tee off.

Most struggled with gales and bracing showers at Royal County Down, a seaside links course beside the Mourne Mountains. Denmark's Soren Kjeldsen and England's Danny Willett shared the early lead at 2 under par.

McIlroy bogeyed half of the course and couldn't hit a birdie. The sellout crowd of 20,000 gasped with each miss.

If McIlroy fails to make the cut Friday, it would be his third straight early Irish Open exit.