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.
Equal access to facilities and resources at St Helen's has seen Swansea Women flourish since being welcomed with open arms last July. Swansea RFC chairman Stephen Hughes and women's captain Siwan Lillicrap are delighted to see rapid progress being made on and off the pitch.
Young referee Ben Breakspear is making rapid strides as a referee. In just over a year he has gone from officiating a college game to being a touchline official during last weekend's RBS 6 Nations clash between Wales and Ireland at Principality Stadium.
Grand Slams, Triple Crowns and British and Irish Lions tours - Sir Gareth Edwards did it all. But what are his favourite moments in what was an amazing career? WRU TV finds out - along with his favourite players of today in the third and final instalment of our series with the greatest rugby player ever.
JPR Williams, Gerald Davies and Mervyn Davies were among those in the Welsh ranks when Sir Gareth Edwards began his international career against France nearly 50 years ago, but who was the player who took the young scrum half under their wing?
Wales head coach Rob Howley and captain Alun Wyn Jones are expecting a physical battle against France on Saturday but both are hoping for another impact from the bench as the men in red chase a top-four world ranking.
It's nearly 50 years since the great Sir Gareth Edwards made his debut as a youngster for Wales against France in Stade Colombes. In the first of a series, WRU TV discovers he pocketed a 'special momento' from the game - something he still has today.
This week, Wales squad players Sam Warburton, Jonathan Davies and Ken Owens took time out to support Operation Net Safe, a joint initiative by the four Welsh police forces to tackle child sexual abuse. The forces are working with the Lucy Faithfull Foundation, the only UK-wide child protection charity dedicated solely to reducing the risk of children being sexually abused, on a campaign called Stop it Now!