By Alexandra Ulmer

RIO DE JANEIRO (Reuters) - Strobe lights, blaring music, and dancing Brazilians may be fixtures at Rio's legendary night clubs, but they aren't usually spotted at Olympic venues.

On Saturday night, however, beach volleyball teams competing in the Rio 2016 Games squared off at a 'midnight party' on the famed Copacabana sand, with athletes playing into the early hours of Sunday for an electrified crowd.

"Brazil isn't playing tonight, so I'm mostly here for the party," grinned professional soldier Sergio Soares, 33, as he walked into the arena carrying a beer.

"And it's a very good party!" he said above speakers blasting hits by Brazilian star Michel Telo, Cuban-American rapper Pitbull, and American pop star Taylor Swift.

The night culminated with American favorites Kerri Walsh Jennings and April Ross thrashing Australian pair Mariafe Artacho Del Solar and Nicole Laird 21-14 21-13 in a game that finished just after 01:00 am on Sunday.

Under the strong Rio sun the previous day, Brazilian female and male teams made winning starts in their hunt for gold.

While it adds pizzazz to South America's first Olympics, the late slot is also part of a wider sports schedule aimed at maximizing television audiences on the U.S. West Coast.

Viewing figures are vital for the funding of nearly all Olympic sports, but athletes and fans have long expressed concern over the rising influence of television and advertisers.

There is also worry the odd hours could unsettle and tire athletes, who may not be able to go to bed until 3-4 am local time following late games.

Swiss Anouk Verge-Depre trained at night ahead of a Saturday game against China, but still said she had trouble talking to partner Isabelle Forrer over the noise and said the artificial light changed her perception of the ball.

In famously laid-back beach volleyball, though, some athletes brushed away concerns over burning the midnight oil.

"Six in the morning or 12 at night, I love to play beach volleyball so that's what I do," Dutch player Alexander Brouwer told Reuters after he and partner Robert Meeuwsen beat Russia on Saturday.

Attendance thinned to about half after midnight, but the atmosphere never dampened.

"It should be fun and enjoyable, that's what sports are all about," said fan Tom Stratwick, 29, who was visiting from London - and planned to explore Rio's other party scene once the volleyball wound down.

(Reporting by Alexandra Ulmer; Additional reporting by Stephen Eisenhammer; editing by Amlan Chakraborty)