Parker, 24, improved to 21-0 and moves on to a shot at either Anthony Joshua or the soon-to-be-vacant WBO belt held by the in-trouble Tyson Fury later this year.
Although the New Zealander was on top throughout, the ending to the contest left a sour taste as Dimitrenko rolled around on the floor on the back of a late body punch.
Dimitrenko was already on his way down from a previous punch and some grappling from Parker, which was followed up by a thunderous shot to the ribs whilst the 34 year-old was on his knees.
Knowing he probably had no chance of winning the fight, Dimitrenko took full advantage of the blow in an apparent bid to get Parker disqualified by referee Marlon Wright.
The official initially didn’t call the knockdown, although as Dimitrenko failed to get up, Wright had no choice but to award the victory to Parker having apparently not seen the finishing punch.
Not a satisfactory ending for Parker as the world title prospect awaits news from the World Boxing Organisation of a potential fight with Andy Ruiz Jr. for the vacant crown.
Also on the bill at the Vodafone Events Centre, heavyweight Izuagbe Ugonoh halted Gregory Tony in two rounds to move to 17-0, whilst Parker’s younger brother John won his cruiserweight debut against Ratu Sailosi Dawai via a majority four-round decision.