LEE WESTWOOD broke a little-known rule at the first LIV Golf event of the year.

The Englishman was in action under the lights in Riyadh last night, finishing joint-25th on seven under par.

Westwood was within distance of eventual winner Adrian Meronk on the 16th hole when he made a huge mistake.

The 51-year-old sliced his tee shot into a stream that was running along the side of the fairway.

His caddie Mick Doran fished the ball out of the water and Westwood then fired onto the green.

But when he arrived to putt in, officials noticed his ball was different to the one he started the hole with.

Westwood’s caddie had clearly scooped out the wrong ball from the stream and reports suggest it was a different “make and model” to the one he should have been using.

It meant that Westy violated a Model Local Rule in place at LIV Golf that requires players to stick with the same make and model of ball throughout the round.

He was consequently slapped with a one-stroke penalty and he scored a double-bogey on the hole.

It proved to be a costly error as Meronk took home £3.2million for his win in Riyadh.

LIV pundit Dom Boulet said: “Well guys, we’ve all been playing this game a long time. That’s the first for me.

“He’s a seasoned pro. Probably the first time he’s ever made that mistake.”

David Feherty added: “I’ve never heard that one either, Dom, most unusual.”