LONDON — John McEnroe — he of ''You cannot be serious!'' call-arguing fame — is quite all right with Wimbledon's latest of many steps into the modern era, choosing technology over the human touch to decide whether a ball lands in or out.
There were no line judges at the All England Club's matches for Monday's start of the oldest Grand Slam tournament, with rulings instead being made by an electronic system that uses recorded voices to announce when a shot lands astray.
''In some ways, the players, and even the fans, miss that interaction, but at the same time ... if it's accurate, I think it's great, because then at least you know that you're getting the right call,'' said McEnroe, who won Wimbledon three times during his Hall of Fame career and is a TV analyst at this year's event for ESPN and the BBC.
''My hair,'' the 66-year-old McEnroe joked, ''wouldn't be quite as white as it is now.''
Wimbledon joins most top tennis tournaments with electronic line calls
The new system puts Wimbledon in line with nearly ever other top-tier tennis event on all surfaces — although the French Open, played on red clay, remains an exception, sticking with judges — and Monday's debut seemed to be mostly seamless, as far as players were concerned.
Indeed, Frances Tiafoe, an American seeded 12th, didn't even notice there were no line judges at his first-round victory.
What he did notice, and chuckled about afterward, was when the chair umpire wasn't even paying all that much attention at one point, grabbing the phone on his stand to place a call and request that more towels be brought to the court on the hottest Day 1 in tournament history.