Mamed Khalidov’s three-year reign as KSW middleweight champion has come to an end.

After suffering his first loss since 2010 in a champion vs. champion superfight this past March to KSW light heavyweight titleholder Tomasz Narkun, Khalidov has decided to vacate his middleweight strap and instead pursue a rematch against Narkun, promotion officials confirmed to MMA Fighting. As a result, KSW will moved forward with a four-man tournament featuring ex-champion Michal Materla (26-6), Olympic bronze medalist Damian Janikowski (3-0), UFC veteran Scott Askham (16-4), and one-time light heavyweight title challenger Marcin Wojcik (11-5) to determine the next KSW middleweight champion.

The four-man bracket begins with Materla vs. Janikowski and Askham vs. Wojcik at KSW 45 in London on October 6th.

“When Mamed decided to relinquish the belt, setting up the four man tournament was the most exciting way to crown the new champion,” KSW co-owner Maciej Kawulski said in a statement to MMA Fighting. “The tournament consists of renowned stars like former KSW champion Michal Materla, the UK’s number one middleweight Scott Askham as well as young wolves like Olympic medalist Damian Janikowski and former light heavyweight contender Marcin Wojcik. This field guarantees a series of thrilling high level fights.”

Khalidov (34-5-2) is a giant star in Poland and has long been considered one of the best middleweights in the world competing outside of the UFC. From 2005 to 2017, the 38-year-old Grozny native racked up a remarkable 30-1-2 run that included victories over a slew of Octagon veterans such as Luke Barnatt, Maiquel Falcao, Kendall Grove, Rodney Wallace, Jesse Taylor, James Irvin, Matt Lindland, Jorge Santiago, and Tor Troeng, among others.

Khalidov’s eight-year unbeaten streak was recently snapped at KSW 42 when he suffered a third-round submission defeat to Narkun in the second of back-to-back champion vs. champion fights for Khalidov. Prior to that, Khalidov defeated KSW welterweight champion Borys Mankowski in front of a record-setting crowd of over 50,000 at KSW 39.

“I can’t fight as often as I did when I was young and I don’t want to block the most stacked division in KSW,” Khalidov said in a statement to MMA Fighting. “The tournament shall crown the new KSW middleweight champion while I am interested in only one fight right now, I am focused on trying to get a rematch with KSW light heavyweight champion Tomasz Narkun.”

KSW is expected to officially announce its four-man tournament with a press conference in Warsaw on Monday.