On June 25, 2011, a 26-year-old Gary O'Sullivan (12-0, 8 KOs) and Robert Long met in the ring in a middleweight bout.
O'Sullivan came in to the fight on a 12-fight win streak with a 66% KO rate, and was fighting after a gap of 1 month and 4 days.
Gary O'Sullivan stopped Robert Long via TKO in the 1st round. O'Sullivan improves his record to 13-0 (9 KOs)
On May 3, 2013, a 28-year-old Gary O'Sullivan (15-0, 9 KOs) and Tadas Jonkus met in the ring in a middleweight bout.
O'Sullivan came in to the fight on a 15-fight win streak with a 60% KO rate, and was fighting after a gap of 9 months and 18 days.
Gary O'Sullivan stopped Tadas Jonkus via TKO in the 3rd round. O'Sullivan improves his record to 16-0 (10 KOs)
On July 15, 2012, a 28-year-old Gary O'Sullivan (14-0, 9 KOs) and Matthew Hall met in the ring in a middleweight bout.
O'Sullivan came in to the fight on a 14-fight win streak with a 64% KO rate, and was fighting after a gap of 4 months and 5 days.
Gary O'Sullivan defeated Matthew Hall via unanimous decision in the 12-round middleweight fight. O'Sullivan improves his record to 15-0
On December 16, 2017, a 33-year-old Gary O'Sullivan (26-2, 18 KOs) and Antoine Douglas met in the ring in a middleweight bout.
O'Sullivan came in to the fight on a 4-fight win streak with a 64% KO rate, and was fighting after a gap of 2 months and 16 days.
Gary O'Sullivan stopped Antoine Douglas via TKO in the 7th round. O'Sullivan improves his record to 27-2 (19 KOs)
On November 15, 2014, a 30-year-old Gary O'Sullivan (17-1, 10 KOs) and Anthony Fitzgerald met in the ring.
O'Sullivan came in to the fight on a 1-fight win streak with a 55% KO rate, and was fighting after a gap of 5 months and 10 days.
Gary O'Sullivan stopped Anthony Fitzgerald via TKO in the 1st round. O'Sullivan improves his record to 18-1 (11 KOs)
On September 13, 2008, a 24-year-old Gary O'Sullivan (4-0, 3 KOs) and Sergejs Volodins met in the ring.
O'Sullivan came in to the fight on a 4-fight win streak with a 75% KO rate, and was fighting after a gap of 2 months and 8 days.
Gary O'Sullivan stopped Sergejs Volodins via RTD in the 1st round. O'Sullivan improves his record to 5-0 (4 KOs)
On April 25, 2009, a 24-year-old Gary O'Sullivan (7-0, 5 KOs) and Marcin Piatkowski met in the ring.
O'Sullivan came in to the fight on a 7-fight win streak with a 71% KO rate, and was fighting after a gap of 1 month and 11 days.
Gary O'Sullivan stopped Marcin Piatkowski via KO in the 1st round. O'Sullivan improves his record to 8-0 (6 KOs)
On May 13, 2017, a 32-year-old Gary O'Sullivan (24-2, 16 KOs) and Chauncey Fields met in the ring.
O'Sullivan came in to the fight on a 2-fight win streak with a 61% KO rate, and was fighting after a gap of 1 month and 25 days.
Gary O'Sullivan stopped Chauncey Fields via KO in the 2nd round. O'Sullivan improves his record to 25-2 (17 KOs)
On October 10, 2015, a 31-year-old Gary O'Sullivan (21-1, 14 KOs) and David Toribio met in the ring.
O'Sullivan came in to the fight on a 5-fight win streak with a 63% KO rate, and was fighting after a gap of 4 months and 17 days.
Gary O'Sullivan stopped David Toribio via KO in the 2nd round. O'Sullivan improves his record to 22-1 (15 KOs)
On May 23, 2015, a 30-year-old Gary O'Sullivan (20-1, 13 KOs) and Melvin Betancourt met in the ring.
O'Sullivan came in to the fight on a 4-fight win streak with a 61% KO rate, and was fighting after a gap of 2 months and 9 days.
Gary O'Sullivan stopped Melvin Betancourt via KO in the 2nd round. O'Sullivan improves his record to 21-1 (14 KOs)