[23] The following week, also in Naples, he won his sixth Challenger title of the year at the Vesuvio Cup, defeating Alexander Ritschard.

In addition, he joined Facundo Bagnis (2016), Juan Ignacio Chela (2001) and Younes El Aynaoui (1998) as the only players to lift six singles trophies in one season on the ATP Challenger Tour.

[25] He won his seventh Challenger title of the season in Tenerife, defeating Feliciano López in the final and becoming the sole record holder for most trophies at that level in a single year.

[29] Griekspoor began his season at the Melbourne Summer Set 1, where he made the quarterfinals after beating seventh seed Dominik Koepfer and Alexei Popyrin.

[34] At his home tournament, the Rotterdam Open, he reached the second round as a wildcard, with a victory over seventh seed Aslan Karatsev, saving two match points in the process for his third top-20 win.

[42] The following week, he successfully defended his Challenger title at the Dutch Open as the top seed, defeating Roberto Carballés Baena in the final.

[43] At the European Open in Antwerp, he won his maiden ATP doubles title with Botic van de Zandschulp.

[44] In Pune, Griekspoor reached his maiden ATP singles semifinal, beating Jaume Munar and Marco Cecchinato, then receiving a walkover against top seed Marin Čilić.

[45][46] At the Australian Open, Griekspoor reached the third round of a Grand Slam for the first time in his career, beating Pavel Kotov and 32nd seed, compatriot Botic van de Zandschulp.

[48] Griekspoor made the quarterfinals in Rotterdam, after defeating Mikael Ymer and eight seed Alexander Zverev, his fourth top-20 win.

It was the first time since Igor Sijsling in 2014 (who also coincidentally was coached by Dennis Schenk[50]) that a Dutch wildcard reached the semifinals at the home tournament.

It was also the first time a Dutch duo, Griekspoor and Brouwer, reached the quarterfinals in singles of the home tournament, since Raemon Sluiter and Sjeng Schalken in 2003.

[57] At the Halle Open, he upset defending champion Hubert Hurkacz to reach back-to-back quarterfinals on grass.

[59] Seeded 12th at the Citi Open in Washington, he defeated Liam Broady, Gaël Monfils, and J. J. Wolf to reach the second ATP 500 semifinal of his career.

[67] Seeded 28th at the 2024 Australian Open, Griekspoor defeated Roman Safiullin and Arthur Fils to reach back-to-back third rounds at the tournament.

[72][73] He reached the second round of Monte-Carlo with a win over Dominik Koepfer, before losing to 11th seed Alex de Minaur.

[74][75] In Madrid, he beat Taro Daniel and upset seventh seed Holger Rune to reach the fourth round of a Masters tournament for the first time in his career.

[79][80] On 22 November, Griekspoor helped the Netherlands reach the final at the 2024 Davis Cup for the first time in their country’s history, after him and Botic van de Zandschulp defeated Germany in the two singles matches.