More usually heard but not seen, the ATP's irreproachable supervisor Norm Chryst made an unscheduled visit to Centre Court last night, writes Matt Westcott.

With Flavio Saretta a set up against Andrew Ilie but tied at 4-4 in the second, umpire Jake Garner called a let when he ruled he was unable to see a return from the Australian that Brazilian Saretta was adamant was out.

When the South American refused to accept Garner's decision, the unmistakeable figure of Chryst was called in to clear the matter up.

"Andrew Ilie was chasing a ball that was close to the net," explained Chryst afterwards. "He was sliding to hit the ball, so the chair umpire was watching Andre Ilie to make sure he did not touch the net.

"Andrew hit the ball and so the chair umpire did not see it bounce. The linesman was unsighted, meaning that he didn't see it bounce either.

"So, being that no-one saw the ball bounce the umpire ruled that a let must be played."

Saretta was insistent that the mark where the ball hit was clearly visible and held play up for more than five minutes while he argued his point.

"We all agreed that that was probably the right mark but the chair umpire did not see it and therefore could not allow it," Chryst said. "The rules of tennis say that if the linesman is unsighted and the chair umpire is unsighted a let must be played. Even though everybody in the stand saw where the ball bounced, the chair umpire was looking at the other player and didn't see it."

Chrsyt said that most players understood the rule and realised that if it happened to them it was simply "bad luck".

"This player thought that because he could show the chair umpire the mark the chair umpire could then rule on it," he said. "But we had to explain that since the chair umpire did not see it, and could not say for certain that that was the mark, a let had to be played."