Marc Limbert's deflected goal 45 seconds into extra time clinched the Welsh Cup for champions Rhyl FC.
Having already won the Welsh Premiership and Welsh League Cup in the last week, Rhyl were given a tough game in Newtown by the league runners-up.
John Toner went close twice for TNS in the early stages, while after the break Rhyl's Mark Powell hit the crossbar with a header. Gary Powell and Stuart Graves also had good chances for the champions, but the match stayed goalless.
That changed in the first minute of the additional 30, however, when Chris McGinn squared to Limbert, whose shot was diverted into the net by TNS defender Chris Taylor. Substitute Justin Perry nearly levelled for TNS four minutes later, but his header struck the woodwork, the same fate that met Rhyl replacement Michael Jackson's shot late on.
However, Rhyl had done enough to lift the cup, which they had previously won only twice, in 1952 and 1953. Manager John Hulse said: "My players showed their character. I told them to keep doing the simple things and that is what happened." Rhyl keeper Paul Smith added: "TNS made it a competitive final, but I felt we just edged it. To win the league was a proud moment, but to secure two other trophies is special."
TNS manager Ken McKenna admitted: "I have to look at myself after this. I will question if I have signed the right players over the last few years. All I have managed is three league runners-up spots and two cup finals."