Sergio Wielzen

! style=background:white colspan=9 |Loses It's Showtime 61MAX world title -61 kg. ! style=background:white colspan=9 |Retains It's Showtime 61MAX world title -61 kg (1st defence).

! style=background:white colspan=9 |Wins inaugural It's Showtime 61MAX world title -61 kg. ! style=background:white colspan=9 |Wins U.M.C. Contender title -61.23 kg.

Sergio Wielzen (born November 1, 1987, in Suriname) is a Surinamese-Dutch super lightweight Muay Thai kickboxer formerly fighting out of Amsterdam, Netherlands for Black Label and FF Carbin.

In 2007 he met fellow up and coming fighter, Mohammed 'Mootje' Kamal, coming out on top in what would be the biggest victory in his career up to that point, winning by decision after five rounds in their B-Class clash.

The two would meet again in a re-match the following year, this time at A-Class level.

Although Sergio suffered a TKO defeat, he also proved that he had an excellent chin fighting against a great boxer, puncher before Sergio Wielzen didn.t came out of his corner in the fourth.

Sergio would truly emerge on the international scene in 2010 when he faced Thai legend Anuwat Kaewsamrit in Geneva, Switzerland.

In a match he was considered a clear underdog, Sergio shocked the Muay Thai world by knocking out the 'Iron Hands of Siam' via a vicious head kick after just 30 seconds.

Due to his results on the local scene – including winning the U.M.C. Contender title against Imed Boukouayel - Sergio would become involved with the It's Showtime organization, making his debut in Milan and defeating local fighter Matteo Lippi by knockout.

Towards the end of 2010, Sergio was called up to face Frenchman Mikael Peynaud for the first ever It's Showtime 61MAX world title.

The fight had some controversy as the match was stopped in the second round after a clash of heads left Peynaud with a cut.

Unable to continue, the fight went to the judge's scorecard, resulting in a technical decision victory for the Surinamese fighter in his home town of Amsterdam.

In December of that year, Sergio was back in action, defending his world title after two months against Japanese K-1 fighter Masahiro Yamamoto in Athens.

This title fight was much more clear cut than the first with Sergio winning by TKO in what was a commanding performance.

In March 2011, Sergio defended his It's Showtime world title once again but was unable to retain his crown, losing by majority decision after five rounds to Karim Bennoui at the event in Brussels.

He lost to Emerson Falcao via unanimous decision at It's Showtime 60 in São Paulo, Brazil on November 10, 2012.

Wielzen got his first win of the year when he knocked out Saša Jovanović in round one at Vendetta VI in Vienna, Austria on December 8, 2012.

He knocked out Alexei Blinov in the first round at Era of Champions in Cheboksary, Russia on March 14, 2013.

He lost a wide unanimous decision to former Lumpinee Stadium champion Kaoponlek after being floored in round one at Glory 7: Milan in Milan, Italy on April 20, 2013.

Wielzen rematched Masahiro Yamamoto at RISE 94 in Tokyo, Japan on July 20, 2013, and fell victim to a second round high kick from the Japanese fighter.

Wielzen competed at the -65 kg/143 lb Thai Max tournament in Meyreul, France on October 19, 2013, defeating Mickael Peynaud by first-round KO in the quarter-finals before losing to Houcine Bennoui by unanimous decision in the semis.

! style=background:white colspan=9 |Fight was for One Championship Muaythai Flyweight Title.

! style=background:white colspan=9 |Fight was for W5 -60 kg Tournament for W5 World Title

! style=background:white colspan=9 |Wins Lion Fight Lightweight World Championship

! style=background:white colspan=9 |Wins KF1 WLF Intercontinental Super-4 (-61.5kg)

! style=background:white colspan=9 |Wins W5 -60 kg Tournament for W5 World Championship

! style=background:white colspan=9 |Fight Was For Muay Thai Warriors 136lbs.

vacant belt.

! style=background:white colspan=9 |Wins W5 world title (-60 kg).

Medio 2015 he switched to Sityodtong Muay Thai & Kickboxing Amsterdam to be trained by Paul and Vincent Pengel.

His nickname is "Samurai" in English.

Despite his deceptively small stature he is known for his explosive power - having won many of his fights by KO or TKO.

He is the former (and first ever) It's Showtime 61MAX world champion as well as the current Lion Fight Muay Thai world lightweight champion

Born in Suriname, Sergio moved to the Netherlands where he became involved in the Dutch national Muay Thai scene beginning his career at C-Class.

An explosive fighter despite his short stature, Sergio worked his way up through the ranks finishing many of his opponents and was becoming noticed as one of the top young prospects at -61 kg in the Netherlands.