Clontribret came from six points down to clinch a thrilling 0-10 to 0-9 win over St Gall's in the Ulster club quarter-final at Clones.
St Gall's scored the opening six points before Clontibret hit back to leave it 0-6 to 0-3 at half-time.
Two Conor McManus frees reduced the gap before St Gall's midfielder Jackson McGreevy was red-carded.
McManus levelled and the county forward also slotted over an injury-time winner for the Monaghan men.
CJ McGourty, Aodhan Gallagher and Michael Pollock were among the St Gall's scorers as they blitzed Clontibret in the early stages.
The Belfast side were six ahead after 10 minutes and Clontibret did not register a score until 12 minutes later.
McManus, Brian Grennan and Vincent Corey fired over and Clontibret also wasted two goal chances as they seized control late in the half.
The momentum remained with Clontibret after the break while a lethargic St Gall's failed to offer little in attack.
McManus tagged on another two frees before McGreevy was shown a straight red card after an off-the-ball incident.
A fourth point in the half from the outstanding McManus edged Clontibret ahead but Pollock equalised and CJ McCourty's point put St Gall's back in front.
The lead changed hands again after scores from McManus and Aodh Curran although Pollock quickly made it 0-9 to 0-9.
McManus flighted over his seventh point in added time to clinch victory and set up a semi-final against Slaughtneil or Cavan Gaels.
"We knew St Gall's would be sharp and they showed it early on, but we dug deep to take a narrow win," said McManus.