LONDON (Reuters) -The All England Club said the chair umpire who faced criticism for his decision following a malfunction of the Electronic Line Calling system was merely following protocols and his absence from the schedule on Monday was due to his rest day.

The ELC system, which is powered by more than 450 cameras across the 18 courts in use, has taken over from the impeccably-attired line judges at the grasscourt Grand Slam this year and received mixed reviews from players and fans.

It came under a harsh spotlight on Sunday when it robbed Anastasia Pavlyuchenkova of a point during her fourth round win over Britain's Sonay Kartal on Centre Court.

Russian Pavlyuchenkova was a point away from winning a game at 4-4 in the opening set when Kartal struck a shot that looked long but there was no call and Pavlyuchenkova stopped play.

An automated voice call of "STOP STOP" rang out before chair umpire Nico Helwerth sought advice from organisers via telephone as television replays showed Kartal's shot was out.

Helwerth ruled that because the Hawk-Eye technology had not tracked the ball, the point had to be replayed as Pavlyuchenkova went on to drop serve but prevailed in the match and suggested that the official should have corrected an obvious mistake.

All England Club chief executive Sally Bolton said Helwerth had followed the rules and that there was nothing unusual about his absence on Monday.

"We have rotation of our umpires regularly. A little bit like the players, the umpires also need rest days throughout the tournament," Bolton told reporters.

"He's fine. Look, it's really important to say that the umpire followed the protocols in place. He did what he needed to do on court and acted entirely correctly."

Bolton said that the All England Club had conducted a review of the ELC system to take the action needed to ensure its smooth functioning going forward.

"We're absolutely confident in the system," she added.

(Reporting by Shrivathsa Sridhar in LondonEditing by Christian Radnedge)