By Sudipto Ganguly PARIS (Reuters) -Rafael Nadal regained his aura of invincibility on clay on Sunday by brutally crushing Casper Ruud to lift the French Open trophy for an incredible 14th time and widen the gap at the top of the men’s all-time list of Grand Slam winners. Norwegian Ruud became the latest victim in a long line of challengers who have unsuccessfully tried to defeat the Spaniard in the Roland Garros final since Nadal won his maiden title on the red clay in 2005. There was a sense of deja vu as the Spaniard, who turned 36 on Friday, completed a 6-3 6-3 6-0 thrashing on a balmy aft…