WBO super-middleweight champion

Stieglitz vacated the WBC International on 22 June, 2009, to fight Karoly Balzsay for the WBO super-middleweight title. At the end of round ten, as a groggy and beaten Balzsay barely wobbled back to his corner, Balzsay's trainer Fritz Sdinek called for help and Balzsay was quickly taken from the ring to the hospital on a stretcher with his neck in a neck brace.^[3] Stieglitz recorded a fifth-round technical knockout of Ruben Eduardo Acosta to retain his WBO super-middleweight title. The fight was stopped at 1:48 to give Stieglitz the victory in his first defense.^[4] On April 17, 2010, he successfully defended his title in Magdeburg against Eduard Gutknecht.^[5]

Stieglitz retained his title with a hard-fought unanimous decision over his Mexican challenger Enrique Ornelas, Andrade's younger brother, at the Freiberger Arena in Dresden. It was a slow start of both fights and little less action but Stieglitz started this fight in style in the second round. The German champion progressed the fight with his sharp jab to give Ornelas some trouble but the Mexican also landed some precise and dangerous shots towards Stieglitz.^[6]

He then made successful defenses against Khoren Gevor and Henry Weber.^[7][8] Stieglitz was supposed to face former three-time titleholder Mikkel Kessler in his hometown of Copenhagen, Denmark to defend his 168-pound belt on April 14, 2012^[9] but Kessler pulled out due to injury. Instead, he defended the title with a unanimous decision win over Nader Hamdan on May 5, 2012.^[10]

Stieglitz vs. Arthur Abraham trilogy

Stieglitz then lost the WBO super-middleweight title to Arthur Abraham on August 25, 2012.^[11] He would rebound with a win over Michal Nieroda on January 26, 2013 before avenging his loss to Abraham and regaining the WBO super-middleweight title with a fourth-round knockout on March 23, 2013.^[12]

His first defense in his second reign as WBO super-middleweight champion was a tenth-round TKO win over Yuzo Kiyota on July 13, 2013.^[13] The result was originally announced as a Technical Decision win for Stieglitz, but was changed to a TKO after the Bund Deutscher Berufsboxer examined the ending of the fight and concluded that Stieglitz did not accidentally headbutt Kiyota. The change was approved by the WBO.^[14]

His second defense in his second reign as WBO Champion was against Isaac Ekpo on October 19, 2013. Stieglitz won via unanimous decision.^[15]

A rubber match with Arthur Abraham took place on March 1, 2014, with the WBO super-middleweight title on the line once again. Stieglitz lost the bout via split decision.^[16]

Retirement

On 23 May 2017 he announced his retirement from professional boxing with a record of 50 wins, 5 losses and 2 draws. The retirement was injury-related, due to the various operations on his left hand and a shoulder injury which had not fully healed.^[17]