Donegal recovered from a four-point interval deficit to end Monaghan's 100 per cent in Division 3A of the Allianz Hurling League in Letterkenny.
Ardal McDermott's charges avenged their second round defeat in Castleblayney with a 1-21 to 2-13 victory. The result paves the way for a likely third instalment between the sides in the Division 3A final.
Early goals from Donal Meegan and Sean Leonard helped the visitors to a 2-7 to 0-9 half-time lead, but a Ronan McDermott goal and three points from Declan Coulter turned the tide in Donegal's favour after the restart.
Tyrone saw off Louth by 1-23 to 2-10 in the other Division 3A clash at Carrickmore.
In the day's only Division 3B encounter, Sligo defeated neighbours Leitrim by 3-17 to 1-15 in Carrick-on-Shannon. Longford beat Warwickshire yesterday to set up a final showdown between the pair.
Donegal - P Burns; D Grant, J Donnelly, P Doherty; J Boyle (0-1), J O'Loughlin (0-1), R Kee; D Cullen, L Henderson (0-8, 7f); D Flynn (0-5), K Campbell, D Coulter (0-5); B Lafferty, R McDermott (1-0), E McDermott. Subs: S Gillespie (0-1) for E McDermott, N Cleary for B Lafferty.
Monaghan - P Bermingham; L McKenna, P Finnegan, B Flanagan; J Guinan, P Treanor, M Murphy; E MacSuibhne (0-2f), C Meegan; F Rafter, T Campbell (0-1), C Boyle; D Meegan (1-9, 0-6f), S Leonard (1-0), B McGuigan (0-1). Subs: N Garland for L McKenna, B Connor for J Guinan, E Leonard for C Boyle, PJ Boyle for S Leonard.
Referee - S Hynes.