Langan shines as Donegal edge past 14-man Cavan
Donegal 1-20 Cavan 1-12
It was only when Jamie Brennan volleyed the ball past Raymond Galligan in the 58th minute that defending champions Donegal could relax against Cavan, who played for most of this match in Ballybofey with only 14 men.
David Phillips' involvement ended after only seven minutes as referee Seán Hurson showed him a straight red card following an off-the-ball incident with Brennan. All-Star Ryan McHugh - sidelined for the last five months due to a concussion injury - made his first competitive outing since Donegal's 'Super 8s' loss to Tyrone last August.
The Kilcar ace jinked his way in for a clever point in the second half as Donegal moved clear. But they needed goalkeeper Shaun Patton to save from Ciarán Brady as Cavan set about getting back into the tie.
Michael Langan kicked six first-half points for Donegal, who led by four (0-10 to 0-6) at the changeover.
Donegal, spurred by a brace from Brennan, had the early momentum, but Cavan levelled briefly as Pierce Smith, goalkeeper Galligan and Conor Madden arched over.
However, with Langan on fire, Donegal moved into a position of strength in the second quarter. They were always one step ahead of Cavan after that and held on to set up a semi-final date with Armagh next weekend.