Tengnueng Sitjaesairoong

In his comeback, Tengnueng Sitjaesairoong went on to participate in the 2014 Omnoi Stadium Weber 154 lbs Muay Thai Tournament at Omnoi Stadium.

On November 8, 2014, Tengnueng defeated Kompetchlek Lookprabat to become the 2014 Omnoi Stadium Weber 154 lbs Tournament Champion.

On December 5, 2014, Tengnueng participated in the one-night King's Cup challenger tournament. In the tournament semis, he knocked out Sweden's Carl N'Diaye in the 1st round. In the finals, he defeated Ilya Grad of Israel by 1st-round KO to win the 2014 King's Cup.

He made his return to THAI FIGHT on April 4, 2015, where he faced Rungrawee P.K.SaenchaiMuaythaiGym at THAI FIGHT CRMA, where he won by three-round decision.

He then defeated Gaëtan Dambo by decision at THAI FIGHT Samui 2015 on May 2, 2015.

Next, he faced Alex Oller at THAI FIGHT Proud to Be Thai: China in China on July 18, 2015, where he proceeded to deliver a 1st-round knockout, the first of many.

On August 22, 2015, he defeated Alka Matewa of Belgium by unanimous decision at THAI FIGHT Narathiwat.

Tengnueng resumed his habit of finishing opponents and began a long streak of knockout victories as he proceeded to beat Aleksei Dodonov via 2nd-round TKO at THAI FIGHT Proud to Be Thai: Moscow on September 17, 2015.

On October 24, 2015, Tengnueng defeated the Lithuanian Sigitas Gaizauskas by 2nd-round KO at THAI FIGHT Proud to Be Thai: Vietnam.

On November 21, 2015, he claimed a 1st-round KO victory over Florian Breau at THAI FIGHT RPCA.

In the final THAI FIGHT event of 2015, THAI FIGHT Count Down, Tengnueng faced the Brazilian José Neto for the 2015 THAI FIGHT 70 kg Championship on December 31, 2015. After connecting on multiple punching combinations, Tengnueng was able to score a 1st-round KO victory. As a result, he was crowned the 2015 THAI FIGHT 70 kg King's Cup Champion.

Tengnueng started 2016 with a 2nd-round TKO victory over Daniel Kerr of Germany at THAI FIGHT Korat 2016 on March 19, 2016.[5]

On April 30, 2016, he secured a 1st-round KO victory over Brazil's Reinato Gomes at THAI FIGHT Samui 2016.[6]

On July 23, 2016, Tengnueng would brutally dispatch Sok Tauch of Cambodia with a 1st-round TKO victory at THAI FIGHT Proud To Be Thai 2016.[7]

On August 20, 2016, Tengnueng was able to secure 2 KO wins in one night at THAI FIGHT KMITL. He first knocked out Yan Naing Aung of Myanmar in the 1st round. He then proceeded to deliver another 1st-round KO over Sinan Uluturk of Turkey that same evening.[8]

At THAI FIGHT London, on September 11, 2016, he beat Sam Gough by 1st-round TKO with a low kick.[9]

On October 5, 2016, Tengnueng defeated Erik Massion of Germany by 1st-round KO at THAI FIGHT Emei.[10]

He would then go on an uncharacteristic three-fight losing streak, including a decision loss to Hamza Ngoto at THAI FIGHT Paris on April 8, 2017.[11] This marked his first loss in THAI FIGHT since September 19, 2012.

After a period of inactivity for most of 2017 and 2018, in which he fought once each year, Tengnueng later returned to THAI FIGHT in 2019 on February 23, 2019, at THAI FIGHT Phuket 2019. This time, he had noticeably put on weight and fought at a heavier 80 kg (176 lbs), as opposed to his previous fighting weights of 70–75 kg (154-165 lbs). His first opponent of the year was Russia's Mike Vetrila, whom he knocked out in the 1st round, keeping his streak of KO wins alive at 12.

On March 30, 2019, he defeated Evgenii Afanasev at THAI FIGHT Mueang Khon 2019 by 2nd-round KO.

Tengnueng seemed to return to his previous form, despite his weight gain, when he delivered a 1st-round KO of Simon Maait of Australia at THAI FIGHT Samui 2019 on April 27, 2019.[12]

However, this was not to last as his performance was called into question when he faced Mohammad Hossein Doroudian of Iran at THAI FIGHT Betong 2019 on June 29, 2019. After uncharacteristically getting knocked down early in the 1st round, Tengnueng seemed hesitant to engage but was able to inflict his own damage in much of the 2nd round. However, the judges deemed the fight to be even after 3 rounds and declared the match a draw, requiring a 4th round to be fought. Both Tengnueng and Doroudian, obviously gassed, were reluctant to engage but the Thai was declared the winner by extra-round decision.[13] This fight ultimately ended Tengnueng's streak of wins by KO at 14.

On August 24, 2019, Tengnueng defeated Aboofazel Goodarzi by 1st-round KO at THAI FIGHT Kham Chanod 2019.[14]

Tengnueng was eventually booked for a rematch with Mohammad Hossein Doroudian at THAI FIGHT Bangsaen 2019 on October 26, 2019. This time around, Tengnueng captured the 1st-round KO victory with a series of high kicks that gradually wore down Doroudian's arms.[15]

On November 23, 2019, Tengnueng faced Shahram Delavar at THAI FIGHT Mae Sot 2019. While he dominated the entire 3 rounds of the fight, Tengnueng was unable to finish off Delavar and ended up getting the win by decision.[16]

On December 21, 2019, at THAI FIGHT: Thai Fest in Patong, Tengnueng faced perhaps one of his most decorated and experienced opponents in the USA's Cyrus Washington, who experienced success competing in Lethwei in Myanmar. While Washington was older and slower, he was able to avoid getting knocked out by Tengnueng and the fight eventually went the full 3 rounds. Nevertheless, Tengnueng took the decision victory and was awarded a THAI FIGHT Kard Chuek Superfight 81 kg belt.[17]

Tengnueng entered his first THAI FIGHT King's Cup Tournament since 2015, this time contesting for the inaugural THAI FIGHT 72.5 kg Kard Chuek King's Cup Championship. He will face Nicolas Rooney in the tournament semi-finals at THAI FIGHT Strong on July 4, 2021. He defeated Rooney by second-round knockout. Tengnueng is scheduled to rematch Nicolas Mendes in the 72.5 kg Tournament Final, whom he previously fought at THAI FIGHT New Normal the year before.[18]

Due to travel restrictions pertaining to the COVID-19 pandemic, Mendes was later replaced by Thomas Carpenter in the Tournament Final. Tengnueng won the fight by first-round knockout via liver shot to win his second Thai Fight King's Cup title.