Dirk Nowitzki is regarded as the best international player in NBA history. Only the sixth player to reach the 30,000-point milestone, Nowitzki believes one day Kristaps Porzingis will best him. The Mavericks’ 39-year-old legend called the 7-foot-3 Latvian “a walking mismatch.’’ “He plays a lot more defense than I ever have, I’ll tell you that,’’ Nowitzki told The Post in New Orleans on Friday after the Mavericks beat the Pelicans. “He’s amazing because he’s got great timing with the long arms on the shot blocks coming out of nowhere. Offensively, he shoots it so easily from deep. He’s scary. He’s added more off-the-dribble now, more turnarounds in the post. He’s going to be a walking mismatch for a long time.” Asked if his career accomplishments will top his own, the 7-foot German said. “He’s way ahead of the curve. My first year I was struggling straight out of Germany and he had that great rookie year. If he stays injury-free, working like that — and I know he will — the sky’s going to be the limit.’’ Nowitzki, who faces Porzingis in Dallas in one week, had worse scoring averages than Porzingis in each of his first three years. In his third season, Porzingis is now averaging 24.5 while Nowitzki averaged 21.8 points. Saturday, Porzingis broke out of a shooting slump in the Big Easy with a 30-point-in-32-minute outing. He was clutch down the stretch, scoring seven straight points in the final two minutes, including a hard right-handed slam with Anthony Davis and DeMarcus Cousins underneath.