WITH an animal grunt of triumph, the butch, frizzy-haired, high-booted wrestler whirled her opponent round by the hair and flung her out of the ring on to the floor. The crowd hooted and Tania turned to acknowledge the applause of her fans and spit four letter epithets at her detractors. Her moment of glory was brief, as with teeth bared and fists clenched, Cinthya Moreno hurtled back through the ropes and lashed out with a vicious kick to the chest. Moaning in pain, Tania collapsed and the spectators jeered and yelled, drowning the referee's count. This is wrestling, Mexican style, and a more popular recreation is hard to find. Bullfighting is no longer politically correct, and futbol just doesn't have the same ''feel good'' feeling. To let off steam and witness the archetypal struggle between good and evil which characterises so much of Mexican life, there's no place like the Arena Mexico, home of ''Lucha Libre.'' This translates as ''Free Fighting'' and there are no prizes for guessing the etymology. It's a mixed crowd who flood into the 5,000 seat stadium, paying around HK$40 for a rickety, hard seat. Old grannies, urchins and trendily clad nymphets. Lucha Libre is very much a fantasy. Teams - usually of two or three men - are categorised as ''Technicos'' or ''Rudos'', or goodies and baddies. Technicos are supposed to be honourable, fight fair, and come up smiling. Rudos have no sense of honour, fight anything but fair, and only smile when they have done something particularly vicious. In a sport patronised mainly by the working class, with its burden of all the vicissitudes of life, identification with the underdog is spontaneous. Two fighters face each other, their team-mates hover anxiously in their corners. The initial moves are routine and stylish, until the taunts and the tussles warm the wrestlers up. A punch a little too hard, a kick slightly off centre, and the battle commences in earnest. A second muscle man enters the ring for a quick stab at an opponent while the referee's back is turned; two against one and the good guy is skidded across the ring. Despite howls of protest and the referee's windmilling arms, they repeat the manoeuvre, till battered and exhausted their victim limps to his corner for a reprieve. His team mate vaults into the ring, and in a moment the tables are turned, with the roars of the audience punctuated by the heady slap of muscle and sinew against canvas. The first bouts of the evening are moderately tame, as these fighters have yet to win their spurs in their chosen form of gladiatorial games. The female events are regarded as little more than an eccentric side show, although they are gradually being taken more seriously. Backstage after her knock-down, stand-up brawl, 22-year-old Cinthya Moreno has put aside her characteristic snarl, and simpers coquettishly like all Mexican maidens are supposed to. ''My father was a wrestler, and so it was natural for me to take it up too,'' she grins. ''I have been fighting for three years, and will probably go on for another five. There are times when it does hurt, but you learn to cope with that. I don't see any reason why women shouldn't fight, but some men don't think it is right. ''We've only recently been able to start fighting in Mexico City. Before, we were stuck in the provinces.'' Women may be able to fight in the same arena as men, but the pay still differs wildly. Top male wrestlers can pick up HK$8,000 an evening, women are lucky to get half as much. But it's the last fights which give the masses their money's worth, and the wrestlers' names are self-explanatory - Pirata Morgan, Ultimo Dragon, Bestia Salvaje. The pirate, the dragon and the beast still cross themselves before entering the arena though, and when one is accidently hurt his aggressors tenderly lead him to the doctor - as soon as they are out of sight of the audience, that is. The play is the thing, after all. And for the coup de grace, as a woozy opponent sprawls in the front row, a Batman look-alike climbs to the top of the ropes and launches himself into mid-air in a suicide dive which spells the end of himself, the fight, and the evening.