Down are through to the semi-finals of the Ulster Football Championship after a thrilling victory over Monaghan at Casement Park on Sunday.

Monaghan, who had beaten All-Ireland champions Armagh in an earlier round, had been four points ahead in the first half.

But Down scored the only goal of the game through Michael Walsh early on the second half and Monaghan were left to rue a number of missed chances.

Down now play Fermanagh in the Ulster semif-finals while Monaghan will gace Westmeath in the All-Ireland qualifiers.

Clockwatch: Down v Monaghan

It was a sweet victory for Down under new manager Paddy O'Rourke after a number of years in the Championship doldrums.

But it only came after a sluggish start as Monaghan built up a nine points to five lead in the first haf hour.

Paul Finlay, the star of Monaghan's win over Armagh, got six of those points with the others coming from Anthony Rooney, Michael Slowey and Thomas Freeman.

But Liam Doyle scored two points late in the half to keep Down well in touch. That brought Doyle's first half tally to four with the Mournemen's other points coming from Colm McCrickard, Gregory McCartan and half-back John Lavery.

Walsh's goal came right at the start of the second half and proved a turning point.

Lavery got his scond point and then McCartan landed another free to see Down go three ahead.

Monaghan, enjoying lots of possession, came back with scores from Raymond Ronagnan and Finlay to cut the gap to just one point.

But Ronan Murtagh and sub James McCartan restored Down's three-point advantage and they kept their noses in front to win by two.

Down: M McVeigh; J Clarke, B Burns, B Grant; J Lavery, A Molloy, M Cole; S Ward, G McCartan; L Doyle, B Coulter, C McCrickard; M Walsh, D Gordon, R Murtagh.

Monaghan: G Murphy; A Rooney, D McKenna, P McKenna; D Duffy, J Coyle, J P Mone; F Lennon, J Hughes; N Corrigan, T Freeman, P Finlay; M Slowey, R Monaghan, D Freeman.