Phil Mickelson's wayward drive cracks a marshall on the head at The Memorial

Phil Mickelson left a huge impression on a unfortunate marshall on the opening day of The Memorial, but it was a painful experience for the volunteer at Muirfield Village.

Mickelson was going along nicely at four under par after 13 holes, but he made a mess of the 14th when he pulled his approach into the hazard to the right of the green and eventually did well to hole a 20-foot putt and limit the damage to a bogey.

The veteran left-hander looked to be heading for more trouble on the par-five next as he tugged his drive too far left and towards the trees but, as the fans scurried for cover, a tournament marshall was not alert to the danger and Mickelson's ball landed on his forehead.

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The official was sent reeling by the blow, but he was soon all smiles when a hugely-apologetic Mickelson arrived with a signed glove by way of compensation.

Mickelson's ball actually ended up in the first cut of rough on the opposite side of the fairway, and he joked: "If your head was softer, I'd be on the fairway!"

And the end result? Mickelson's second found a greenside bunker, but he splashed out to three feet and holed the putt to add to his vast collection of adventurous birdies!

Watch the video to see how Mickelson got a "helping header" from a marshall at The Memorial...