PORTRUSH, Northern Ireland -- Rory McIlroy's start to The Open in his native Northern Ireland couldn't have been much worse.

McIlroy, the favorite to win the 148th Open Championship at Royal Portrush Golf Club, hit his tee shot on the first hole out of bounds and ended up with a quadruple-bogey 8 on the par-4, 421-yard hole.

McIlroy's opening drive hit a woman and cracked the screen of the mobile phone in her pocket.

After a one-stroke penalty, McIlroy hit his second tee shot into the deep rough on the left side of the fairway. His fourth shot was low and ended up in even thicker rough on the left side of the green. He was forced to take an unplayable lie near the green.

Then he made a great pitch shot to about 2 feet and two-putted for 8.

After the opening hole, McIlroy's odds to win The Open dropped from 8-to-1 to 33-to-1 on online betting sites. He also hit his opening tee shot out of bounds during his practice round Wednesday.

According to ESPN Stats & Information, it's the first time McIlroy started a major championship with a double-bogey or worse since the 2012 Masters, when he opened with a double-bogey. It's only his second quadruple-bogey in a major (he had one on the 11th hole in the final round of the 2013 U.S. Open at Merion) and only the fourth in his PGA Tour career.

No major winner in the past 20 years started a tournament with worse than a double-bogey.

McIlroy's forgettable start spoiled The Open's highly anticipated return to Royal Portrush, where it hadn't been played since 1951. McIlroy, 30, grew up in nearby Holywood, and he set the Royal Portrush course record with a 61 when he was 16.

He talked about the pressure of playing in The Open in his native country Wednesday.

"I'm just treating this like any other Open Championship," McIlroy said. "I've played well here for the last few years. I've played well on this golf course. So I've just got to go out and hit the shots and stay in the present. If I just keep putting one foot in front of the other, hopefully by Sunday night that will be good enough."

McIlroy wasn't the only player who saw everything fall apart on a hole. David Duval posted a 13 on the par-5 seventh hole.

The 2001 champion also had a quadruple-bogey 8 on the fifth at Royal Portrush. He birdied the first two holes and is 11 over through eight.

Duval won at Royal Lytham & St. Annes 18 years ago but now spends more time as a golf commentator than he does playing professional events.

Information from The Associated Press was used in this report.