[1] He was one of only two Germans to make the fourth round of the 1967 Wimbledon Championships, with wins over John Pickens, Onny Parun and Giordano Maioli.

[3] His opponent in the final, Hans-Jürgen Pohmann, partnered with Plötz at the 1969 French Open, to reach the fourth round of the men's doubles.

He was a finalist at the 1974 German Open in Hamburg, a clay court tournament on the Grand Prix circuit.

[4] In 1975 he started the year well by making the quarter-finals in Basel and semi-final in Cairo, for which he was rewarded in April with his highest ranking, 65 in the world.

In the Canadian Open that year in Toronto he played as a qualifier and had a win over Björn Borg, en route to the quarter-finals.