Phil Mickelson handed a six-year-old a $99 tip for a glass of lemonade at his stand

Brother and sister set up a lemonade stand outside the Memorial Tournament

Phil Mickelson was an early mover as he birdied two, three and four (Getty Images)

American golfer Phil Mickelson handed a pair of kids a $99 (£65) tip for a glass of lemonade.

Roland van Karsen, six, and his eight-year-old sister Elise set up a lemonade stand at the corner of Carnoustie Drive and Kilbannan Court outside the No 10 gate at the Memorial Tournament in Dublin, Ohio.

The two youngsters were selling their drink for $1 a time. Mickelson, ranked No 19 in the world, bought a glass, paid with a $100 bill and then allowed the two kids to keep the change.

Elise hadn't recognised Mickelson but Roland, a keen golfer, had.

"All we were doing was sitting here, and all we saw was this white car drive up, and it was close, and he said ‘Can I have a glass of lemonade?’ and all it took was one little thing for him to give us a good tip," Roland told the Columbus Dispatch.

At first the pair thought it was $10. "Whoa", was the reaction of Elise.

"We didn’t take any pictures, we didn’t get any autographs," their mum, Ann, told the paper. "It happened so fast that we were kind of stunned. What a great guy, though, right? So generous and the kids will have a memory like that forever."