Nadal had the toughest opposition

From the emergence of Roger Federer as the world's best tennis player in 2004 up to the early 2020s, men's tennis has been dominated largely by the "Big Three" players: Federer, Rafael Nadal, and Novak Djokovic. While each of the three has had unprecedented success and has had to contend with the other two on numerous occasions, Nadal has faced a relatively steeper challenge from the Big Three era than either of his rivals have. Federer, as the oldest of the three and first to achieve breakout success, was able to accumulate a large portion of his Grand Slam titles in a relatively weaker era of competition. Federer won 12 Grand Slam championships from 2003-2007, dominating less accomplished players while Nadal and Djokovic were still developing. Djokovic, as the youngest and last to come into his prime years, similarly benefited later in the Big Three era. Thus Nadal, in between the ages of Federer and Djokovic, had his athletic prime years overlap on either end with the prime years of either Federer, or Djokovic, or both. This forced Nadal to win his biggest championships under the most difficult possible circumstances: in direct competition with not one but two other legitimate candidates to be considered the best player of all time. Yet in spite of this fierce competition, Nadal succeeded, and compiled a list of victories comparable to those of his rivals and any other player in history.