Here is a list of Steenis's best fights. For a list of Steenis's losses, refer to "Costello van Steenis Losses".
On November 30, 2018 Costello van Steenis faced off against Chris Honeycutt in a middleweight bout at age 26. He was coming in with a record of 11-1 (8), and Honeycutt was 30 years old and with a record of 11-2 (6). Steenis won the fight via 3-round split decision.
On July 19, 2025 Costello van Steenis fought Johnny Eblen in a middleweight title fight for Eblen's PFL World Championship title. Steenis was 32 years old and with a record of 17-3 (12), and Eblen was 33 years old and with a record of 16-0 (7). Steenis stopped Johnny Eblen via 5th-round choke-out and is crowned the new PFL middleweight champion.
On October 29, 2022 Costello van Steenis faced off against Kamil Oniszczuk in a middleweight bout at age 30. He was coming in with a record of 14-2 (10). Steenis stopped Kamil Oniszczuk via submission.
On May 17, 2024 Costello van Steenis faced off against Gregory Babene in a middleweight bout at age 31. He was coming in with a record of 15-3 (11). Steenis stopped Gregory Babene via submission.
On September 26, 2020 Costello van Steenis faced off against Fabian Edwards in a middleweight bout at age 28. He was coming in with a record of 13-2 (9), and Edwards was 27 years old and with a record of 9-0 (6). Steenis won the fight via 3-round split decision.
On May 25, 2018 Costello van Steenis faced off against Kevin Fryer in a middleweight bout at age 25. He was coming in with a record of 10-1 (8). Steenis stopped Kevin Fryer via TKO.
On October 20, 2017 Costello van Steenis faced off against Steve Skrzat in a middleweight bout at age 25. He was coming in with a record of 9-1 (7). Steenis stopped Steve Skrzat via TKO.
On June 22, 2019 Costello van Steenis faced off against Mike Shipman in a middleweight bout at age 26. He was coming in with a record of 12-1 (9). Steenis stopped Mike Shipman via KO.
On November 29, 2024 Costello van Steenis faced off against João Vitor Dantas in a middleweight bout at age 32. He was coming in with a record of 16-3 (12). Steenis stopped João Vitor Dantas via KO.
