Ciaran Considine scored a vital goal after nine minutes as Clare made it three league wins out of seven to guarantee themselves a quarter-final spot at Clones yesterday.
Third-placed Monaghan went into the game harbouring hopes of the play-offs, but those ambitions were made to look way off beam as Clare ran riot in the first half to lead 1-4 to 0-4 at the break.
Declan Smyth was Monaghan's only scorer from frees in the first half, but if they were ineffective up front, they were even less so in defence. Only the post denied Ger Keane a further Clare goal.
Peter Duffy scored the home side's only point from play eight minutes into the second half. But Monaghan lacked flair and invention and it was over as a contest when Monaghan goalkeeper Glen Murphy was beaten by a cruel deflection off Donal O'Sullivan five minutes into injury time.
CLARE: J Hanrahan; A Malone, N Hawes, J Enright; P O'Gallagher, B Rouine, C Nagle; D Russell, D O'Sullivan, (1-0); J Daly, P McMahon (0-1), D O'Driscoll; G Keane (0-3), C Considine (1-0), M Daly (0-3). Subs: B Considine for P Rouine, 17 mins; J Considine for J Daly, 36 mins; O O'Dwyer for G Keane, 54 mins.
MONAGHAN: G Murphy; C Flanagan, D McDermott, N Marron; E Murphy, J Coyle, J Conlon; J Coyle, F McEneaney; D Swift, P Duffy (0-1), D Freeman; D Smyth (0-4), M Daly, S McGinnity. Subs: G McGuirk for M Daly, 50 mins; F McCaul for S McGinnity, 50 mins, C Ronaghan for D Swift, 54 mins.
Referee: H O'Brien (Roscommon).