A proverb meaning that no matter how good you are, there is always someone better — a reminder not to be arrogant.
彼は料理が得意だが、上には上がいると知って謙虚だった。
He was good at cooking, but knowing there's always someone better, he remained humble.
テストで満点を取ったが、先生は『上には上がいる』とさらに努力を促した。
Although he scored full marks on the test, the teacher said 'there is always someone better' to encourage further effort.
スポーツの世界では才能は重要だが、いつも上には上がいることを忘れてはいけない。
In sports, talent matters, but one must not forget that there's always someone better.