Welsh League Division One leaders Cambrian and Clydach were too good for Monmouth Town's Kingfishers on a fine day in the Rhondda as any thoughts of a giant-killing were ended for another season.
Cambrian were on the back of a 17-game unbeaten run stretching back to February and it may have been a different story if the Town could have kept home advantage, having to switch the fixture because of a clash with rugby.
A below-par first half performance by the Kingfishers made it simple for the surprise hosts as Lewis conceded a 12th minute penalty.
A breakaway goal on 31 minutes gave the table toppers a two-nil half-time lead, and Cambrian looked every inch two divisions above the Kingfishers with stronger players and quicker, more decisive movement.
To their credit, Town came out in the second half looking much improved and were much more competitive around the pitch with Hughes to the fore and Smith trying to inject more urgency.
Town forced a number of smart saves from the Cambrian keeper.
In contrast, Williams in the town goal had very little to do.
On the hour, a Monmouth goal might have changed the complexion of the game as they pressed for a way back into the cup tie.
A fine break by Bertorelli ended any such hopes and showed the difference in standard with a quick clinical break and finish.
Town stuck at it and kept competing, and deserved a consolation with a fine header by substitute Lewis, who had replaced the hard-working Bowen.