Early Newport pressure came to nothing although Scott Sneddon did put the visitors ahead on 20 minutes. Newport dominated most of the play and elusive winger Frewen crossed in the 27th minute. Sneddon's conversion put the visitors 13-0 ahead.
Newport then appeared to lose their way and dangerous full-back Jonathan Phillips raced over for Aberavon but the conversion went wide.
Newport centre Alan Awcock was yellow carded for dangerous use of the boot on the half-time whistle with the Wizards making use of the extra man. Centre Ben John went over and Davies converted giving Newport a 13-12 half-time lead.
Things got worse for the visitors in the second half as Jamie Davies slotted over a penalty to give the Wizards a 15-13 lead.
Sneddon levelled things up with a penalty but the Wizards were now growing into the game and scrum-half David Pritchard evaded tacklers to score although Davies again missed the kick.
There were no further scores until Frewen's dramatic injury time try and Newport held out for their first win at Talbot Athletic Grounds since 2009.
Newport Man of match : Scott Sneddon.