His interest in the score is as intense as the other spectators but his priority is to transmit the result of each point to someone often several thousand miles away via an electronic device in his pocket.
Meet the "courtsider", someone whose purpose is to exploit the seconds between the action on court concluding and the scores reaching the outside world via the umpire's digital scorecard.
He might be placing bets on matches from the side of the court himself or sending live scores or statistics to a third party, who can use the information to bet for themselves or their clients.
Getting their information out a few seconds earlier gives them the opportunity to bet before the odds are adjusted by the bookmakers or on betting exchanges like Betfair.
Bookmakers know all about the time delay, of course, and that is why they do not allow customers to gamble on the following point with most of the betting in these situations done on the outright match market.
Courtsiding came into focus at this year's Australian Open when a 22-year-old British man was arrested on the second day of the tournament and charged with "engaging in conduct that would corrupt a betting outcome".
Daniel Dobson will appear again at Melbourne magistrates on Thursday.
Defenders of courtsiding say it is not related to match-fixing or illegal betting and that gaining the edge over a bookmaker should not be a criminal offence.
Australian Open organisers, however, feel it is part of a wider picture that threatens to damage the sport.
"What I'm talking about is the integrity of the sport," Craig Tiley, the CEO of Tennis Australia and the tournament director of the Australian Open, told Reuters.
"Yes, they're not affecting the match, they're not affecting the outcome or the score, but they are utilising a small opportunity that exists in the sport to gain a benefit out of it that arguably could be illegal, maybe some cases legal.
"My view is that what they're doing is pushing the boundaries of what you would consider to be acceptable in integrity, relative to the sport."
The Australian Open, like the men's ATP and women's WTA professional tours, uses a company called Enetpulse to distribute its live scores and statistics to bookmakers.
It is a considerable source of revenue for the authorities, a point of contention when a number of tournaments accept gambling sponsorship but ban betting on site.
Chris Kermode, the new chairman and CEO of the ATP Tour, told Reuters that he did not believe courtsiding was a big problem and that eliminating match-fixing was a bigger priority.
A number of players have been implicated and investigated over possible match-fixing, which seems to be more prevalent at the lower end of the tour, where prize-money is low and attention is scant.
In 2008, the Tennis Integrity Unit was set up to reduce the number of these incidents and several players have fallen foul of a rule banning them from betting on any match on the tour.
Players are told they must report any illegal approach by someone offering them money to throw a match or influence its outcome.
The ban on betting extends to the accredited media, the idea being that they may have seen or heard something from a coach or player and therefore be able to get an unfair advantage.
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- Australian Open