Betting is a rampant phenomenon in international tennis.

The racket sport, with a 15 seconds difference between a live match and online scoring, provides ample opportunity for betting from the venue.

And in countries where betting is legal, it happens on a regular basis.

However, for the Chennai Open it came in as a surprise.

The organisers of the tournament unearthed a betting racket, the members of which allegedly belong to an international betting syndicate.

Four foreign nationals -- two Germans, an Italian and a Russian -- were caught betting live from inside the stadium premises on Thursday.

However, even though betting is illegal in India [ Images ], no official case was filed against the above four, with them being let off with a warning.

Sources though confirmed that the Chennai police had interrogated the four foreigners, taken their photographs and made a note of their passport details. The information will be circulated to the other ATP tournaments to help them deal with such a situation.

As regards the Chennai Open per se, the security at the tournament has been beefed up and officials are keeping a watchful eye on any similar activity.