Mahan in penalty mix-up

Hunter Mahan and Jamie Donaldson suffered a rare two-shot penalty at the US Open after they played each other’s golf ball by mistake during their second round.

The pair played the wrong ball on the 18th fairway, their ninth of the day, and when the error was noticed they had to return to the spot from where they had hit their second shots and drop the ball under penalty.

For Welshman Donaldson it did not really affect the outcome of his tournament as he shot 81 to leave him 11-over-par and comfortably missing the cut.

For Mahan, however, it could well cost him his place at the weekend as he finished on six-over, and just one shot outside of the cut line when he finished his round.

"It was one of those things I couldn't explain to you," said Mahan. "Off the tee it looked like that's where my ball should have been and I couldn't explain to you how it ended up where it did. Just got to pay more attention.

"It's one of those fluke things. I've played a lot of rounds of golf now and it's happened maybe one time before."

Mahan's caddie John Wood was quick to shoulder the blame, adding: "It was 100 per cent on me. I was the first one to the ball. It's a rhythm you get into as a group. And if I'm the first one there, I go to a ball, I get a yardage. There's no reason for Hunter to think that I went to the wrong ball or Jamie or Mick (Donaghy, Donaldson's caddie) to think that I went to the wrong ball. So I think it's mostly mine.

"Off the tee it looked like Hunter's (ball) was in the left centre and Jamie's was on the left edge. And we got up there and they were switched and we didn't realise it."

Players usually mark their ball in a distinctive way to prevent such mistakes, but Wood added: "They both have kind of an interesting slash across the number, which is not a very common marking. The only thing I can think of is I saw a slash and assumed it was Hunter's, because it's not a very common marking.

"But still, it's hard to believe. I don't believe I did something that epically dumb, but I did. You can't imagine yourself doing something colossally as stupid as that, but I did it. I won't forgive myself very soon after this.

"Hunter was great about it. He had no reaction at all. He went back and hit a good shot and ended up turning around and making birdie on number one."