Marterer made his ATP main draw debut at the MercedesCup in Stuttgart where he was given a wildcard into the singles event.

[2] At the Sofia Open, he reached his first ATP quarterfinal, where he lost to eventual champion Mirza Bašić in three sets.

He reached his first ATP semifinal at the BMW Open in Munich where he lost to sixth seed Philipp Kohlschreiber.

[3] For both players it was their first appearance at the French Open, but it was Marterer who triumphed in four sets to reach the third round for the second consecutive Grand Slam.

209, he qualified for the main draw at the 2021 US Open after two years of absence but lost in the first round to Steve Johnson in a tight four-set match.

He reached the semifinals at the 2023 European Open in Antwerp as a qualifier, defeating seventh seed Richard Gasquet, Nuno Borges and Hugo Gaston.

He became the third qualifier in tournament history to reach the semifinals after Tsitsipas in 2017 and Brooksby in 2021 (both lost to Schwartzman in the semis).