The home side contained a number of new faces but it was old favourite Dai Langdon who ran the show for the Blacks, racking up all 13 of their first half points.
Langdon's performance aside, it was a disappointing result for the home crowd as Rosslyn Park ran out winners. Within the first few minutes, the visitors looked like they were ahead but a score from a scrum was ruled out for an infringement.
And although it was the English side with all the pressure, Neath opened the scoring with the first try of the day. A strong kick chase saw Edwards' side retain possession with scrum half Josh Davies passing on to James Goode who fed Langdon to touchdown just left of the posts and add the easy conversion.
The lead didn't last long, Conner McDonald replying for Rosslyn Park with Sam Katz adding the extra two.
With minutes left on the clock before half-time, both teams were pushing hard for an interval lead.
And the left peg of Langdon ensured it was Neath who held the advantage, a penalty and a superb drop goal just before the break making the score 13-7.
Neath struggled in the opening minutes of the second half. Tries for Rosslyn Park from Peter Hodgkinson and Paul Unseld, with Katz successfully converting both, took them ahead for the first time in the game.
With a deficit to turn around, inside centre Adam Jones scored his first try for Neath to give them hope.
This was as good as it got though as Neath's hopes of a win evaporated with three converted tries in the last 10 minutes from Rosslyn Park ending the game as a contest.
Unseld added his second with touchdowns from Darrell Ball and Charlie Broughton following.
The game may have gone but Neath continued to test the opposition defence right up until the final whistle, full back Ceri Young squeezing over in the right hand corner.
Neath's next pre-season game sees them take on Carmarthen Athletic in their final hit-out at The Gnoll this Friday.