One of the selling points of the Davis Cup has long been the boisterous atmospheres created by partisan crowds cheering on their teams.

Etiquette is generally observed but, of course, there is a line.

Novak Djokovic felt that was crossed when a small group of British fans tried to drown out his interview with musical instruments after their team were knocked out by Serbia on Thursday in Malaga.

The world number one was in no way suggesting the noise created between points and during the changeovers should be diluted.

British captain Leon Smith agrees the best Davis Cup ties are the noisy ones.

"When it's flat and dead and no-one's clapping, no music, it's pretty boring," Smith said.

"That's one of the things that's good about Davis Cup and the team competition, that actually you're kind of meant to make noise.

"There are always comments which can go a bit over but I don't think it's that bad.

"I would hate to see it quietening down, because there's enough quiet tennis as it is. If anything, that atmosphere is good for us."

After securing Serbia's place in the last four with an assured and drama-free win over Cameron Norrie, Djokovic suggested the noisier British fans should "learn how to show respect" before telling them to "shut up".

"They can do whatever they want, but I'm going to respond to that. That's what happened," Djokovic said.

Djokovic is a player who generally thrives in a spicy atmosphere, feeding off the energy of a crowd - even when it is negative - and channelling into his performance.

Having won a men's record 24 Grand Slam titles and being widely considered as the greatest player of all time, it clearly works for the 36-year-old Serb.

Djokovic's point was that what perhaps was intended to be 'banter' by the British band had strayed into disrespect.

The International Tennis Federation, which organises the Davis Cup and the women's Billie Jean King Cup, remains happy for supporters to bring along instruments.

The tie between Britain and Serbia in Malaga was a colourful occasion, with both sets of passionate supporters singing, chanting and making noise to create an atmosphere reminiscent of matches in the competition's previous home-and-away format.

Andy Murray, who missed out through injury, echoed the thoughts of many tennis fans when he said the 123-year-old men's team event would not be the same without the noise.

On Friday, the former world number one showed his appreciation for the British fans - estimated at almost half of those in attendance at the 11,500-capacity Palacios de Deportes Jose Maria Martin Carpena.

"Huge thanks to all the fans who made the big effort to travel out there and create a brilliant atmosphere for the players," said Murray.

Many tennis federations - including Britain's Lawn Tennis Association - contribute to trips abroad of some fans in order to create a din of support for their team.

The British band is part of a travelling group - known as the Stirling University Barmy Army - which has been backing the nation's players since 2009 with support from the LTA.

The LTA said it would "always encourage" British supporters to "behave with respect" for opposing teams and players.

"Passion is a unique component of the Davis Cup and [in] a competition where emotions run high, we are lucky to have strong travelling support," it added.

It is clear those at the heart of the sport unanimously want the emotions stirred by the Davis Cup to remain - as long as that passion remains on an accepted side of the line.