The Blues had produced a superb forward performance but the Dragons had the inspirational Percy Montgomery behind a hardworking pack and Morgan always had an eye for an opening.
Rhys Williams gather dived over for the opening Blues try after only eight minutes and MacLeod added a penalty to signal 20 minutes of total domination by the visitors.
After 25 minutes, however Morgan brought the home side back into it with his first try. While only 10 minutes later a break by Montgomery carved open the Blues defence and Sione Tuipulotu completed the move with a try converted by Ceri Sweeney which gave the Dragons a 12-8 lead at half-time.
The third quarter was something of a stalemate with MacLeod and Sweeney exchanging two penalties apiece to make it 18-14. However with only two minutes remaining, Morgan came in from the wing to take a midfield pass from Sweeney and slice through for his second try, effectively winning the
game for the Dragons.
Sweeney converted and, although replacement Jonny Vaughton grabbed an injury-time try for the Blues which was converted by MacLeod, the Dragons held on to gain revenge for their early season defeat at Cardiff Arms Park.