Djokovic gets physical with chair ump over ball mark

The ATP typically does not use its Hawk-Eye technology in clay-court events, as its ball-spotting mechanism is not as accurate on clay as it is on other surfaces. This leaves the chair umpire to rule on the controversial spot of a shot based on the ball mark, which can be a pretty unscientific process.

Carlos Bernardes found himself in such a position while officiating Novak Djokovic and Rafael Nadal's quarterfinal match at the Rome Masters on Friday.

Bernardes has something of a fraught history with Nadal, but on this day he ruled in the Spaniard's favor, calling his turnaround, down-the-line forehand good, when it appeared to be wide. (On the telecast, Hawk-Eye showed the ball landing just out.)

Djokovic called Bernardes down from his chair to have a look at the mark, but grew frantic when the umpire appeared close to marring it with his demonstrative finger.

According to the ATP rulebook, Djokovic could be subject to a fine up to $10,000 for "the unauthorized touching of an official."

He went on to win the game, and the match - 7-5, 7-6 (4) - beating Nadal for the seventh straight time to advance to the semifinals.

"After the match they told me the ball was out, which I'd seen," Djokovic said in his post-match presser. "He didn't. But it's okay. Everybody makes a mistake.

"The only thing I minded with Carlos is he was actually touching the mark, and he was touching the line. So I don't know. He was kind of creating his own mark."