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The Hawk-Eye electronic line-calling system has been tennis's greatest innovation of the 21st century.

Now an accepted part of the scene on the big showcourts at major events around the world, it entertains spectators by resolving the eternal question of who is correct about line calls - the linespersons, the players or the umpire?

Well, at least to within 3.6 millimetres, the margin of error claimed by Dr. Paul Hawkins, the inventor of Hawk-Eye. Actually, he believes it is much less than that.

Hawk-Eye, though pretty well universally accepted by players and tournament officials, had a significant hiccup last week during the Andy Murray-Ivan Ljubicic quarter-final match at the BNP Paribas Open at Indian Wells, California.

At deuce, 4-4 in the second set with Ljubicic serving, Murray put up an extremely high lob that bounced on Ljubicic's side near the net. He looked as if he would not play the ball because it was out - it would have been a fairly easy smash - but then hesitated for an instant because the call was a little slow coming. That hesitation made Murray, as he later explained to Ljubicic when they shook hands at the net after his two-set win, decide to challenge the call. It was a typical "why not take a chance" challenge that players will make when their opponent's body language suggests the call could be doubtful.

When video boards in the stadium revealed the ball was on the line, Ljubicic was dumbfounded because he was sure the ball had been out. Umpire Ali Nili agreed with him but could not change the call.

The incorrect call made it break point against Ljubicic and he went on to lose his serve. Happily, he broke Murray in the next game, when the Briton served for the match, to make it 5-all. So the bad call did not lead directly to his eventual defeat.    

It turned out that the ball mark shown on the video screens in the stadium was actually the second bounce. Part of the problem may have been that Murray's lob was so high that the Hawk-Eye system lost track of it. In any case, the following is a release from Hawk-Eye explaining what happened:

HAWK-EYE INDIAN WELLS 2009 - MURRAY V LJUBICIC

In the 3 years and over 10,000 challenges, Hawk-Eye produced its worst error in the Murray vs Ljubicic match at Indian Wells, when a ball which was OUT was shown on the video screens to be IN.

The cause of this error was not due to the core tracking part of the system, which functioned exactly as it should have done. The error was due to the incorrect bounce being replayed on the video board. Due to the nature of the shot, the 1st and 2nd bounce appeared in similar places, and the 2nd bounce was shown on the screen instead of the 1st bounce.  This mistake was partly due to an error by the operator who is responsible for displaying the correct bounce mark, but the system has also been modified as a result of this incident to ensure that the operator always goes to the correct bounce mark, and prevent this happening again.   The purpose of this document is to communicate the reason for this error, and to unreservedly apologise to all concerned, in particular Mr Ljubicic.

Unfortunately, despite Nili and Ljubicic believing the ball was out, Hawk-Eye rules and the call could not be changed.

"He [Nili]asked for them [Hawk-Eye officials]to reconfirm the call, which they did" said Gayle Bradshaw, the ATP's executive vice-president, rules & competition. "Once confirmed, then the chair [umpire]cannot overrule."

Clearly, Hawk-Eye rules. These days in tennis, in stadiums equipped with Hawk-Eye, the final court of appeal on line calls is a machine.

PRAISE and POT SHOTS:

PRAISE: Hats off to Frederic Niemeyer and Frank Dancevic. Both had excruciating singles defeats on the final day of Davis Cup in Toronto three weeks ago when Canada lost 3-2 to Ecuador.

The well-liked Niemeyer, 32 and clearly in the homestretch of his career, bounced back by winning the $10,000 ITF Futures event in his hometown of Sherbrooke, Que., last Sunday, defeating Charles-Antoine Brezau of France 6-1, 6-2 in the final.

As for Dancevic, in his first event since the Davis Cup debacle, he has qualified for this week's $4.5-million (U.S.) Sony Ericsson Open in Miami. The No. 117-ranked Dancevic defeated Nicolas Mahut of France and, in the final round, qualifying top seed, Dudi Sela of Israel, 6-2, 6-4.

Ironically, Sela was a Davis Cup hero the same weekend Dancevic lost a heart-breaker to Nicolas Lapentti after leading by two sets to one and 4-1 in the fourth set. Sela won both his singles matches in five sets (over Andreas Vinciguerra and Thomas Johansson) as Israel upset the host nation in Malmo, Sweden.

POT SHOT: Why is Serena Williams now scheduled to play four weeks in a row? The world No. 1 is playing the $4.5-million (U.S.) Sony Ericsson Open in Miami the next two weeks before going to Marbella, Spain, to play on red clay. Then she is slated to return to the U.S. the following week to play on 'green' clay (a.k.a. Har-Tru) the following week at the $1-million (U.S.) Family Circle Cup in Charleston, S.C.

The Marbella event has only $220,000 (U.S.) in prize money, so Williams is obviously making the jaunt across the ocean to receive a generous appearance fee for showing up.

Always somewhat injury-prone, what are the odds she plays all three events to conclusion?

 

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