Despite leading 19-0 until the final minute of the opening half, the Wizards struggled to overcome a spririted Llanharan outfit, who were fit and played withgreat heart.
Early tries by wing Richard Carter and centre David Hawkins were followed by a second from Hawkins with two converted by Jamie Davies.
Llanharan got on the board with an injury-time penalty by Wayne Jervis, but within five minutes of the restart, Carter went over again for Davies to convert.
Llanharan replied with a try by hooker Alan Williams and Jervis kicked a penalty, though Davies added a further Aberavon score with a penalty shot.
Aberavon were rocked again when flanker Ceri Jones went over for a last-minute try that Jervis converted from the touchline.
In Division One, leaders Maesteg won a local derby by 37-15 against Bridgend Athletic and scored five tries through wing Alun Brown (2), centre Paul Morgan, veteran scrum half Kevin Ellis and fly half Mark David.
David converted three and placed two penalty goals, but the Athletic responded with tries by Gavin Pound and Andy Tollentino and skipper Stuart Morris placed a conversion and penalty.
Dodgy tattoos, carthorses, Avatar and soft chins are revealed by Wales Sevens players Tom Williams and Sam Cross as they profile the Wales Sevens squad taking part in Hong Kong this weekend in the latest round of the HSBC Sevens World Series.
The youngest member of the Wales Women's squad, Keira Bevan, is hoping to repay the faith shown in her when she starts her first Six Nations game against Italy tomorrow evening in the final round of the championship.
Sevens head coach Gareth Williams is a happy man after drafting in full internationals Rhodri Williams and Adam Warren for the next two rounds of the world series in Hong Kong and Japan, as WRU TV's Graeme Gillespie discovers.
Gemma Rowland has had a 'whirlwind' start to her international career with Wales. Despite losing to France, she is confident Wales Women can bounce back and claim a rare Triple Crown against Ireland on Sunday, as WRU TV's Graeme Gillespie discovers.