Michael Murphy kicked six points as Donegal came from a point down at half-time to overcome Ulster rivals Down at Ballybofey, 0-12 to 0-07.
The All-Ireland champions, who trailed 0-05 to 0-04 at the interval, upped their game in the second period and outscored Down by eight points to two.
The introduction of All-Star Neil Gallagher at midfield turned the tide for the hosts who were pedestrian for long period in the opening period. Donegal started with 11 of their All-Ireland winning team.
The game also marked a competitive debut for 18-year-old defender Ryan McHugh, the younger brother of Mark McHugh.
Down had their noses in front at half-time as they led 0-05 to 0-04 with the Tir Chonaill posting two late points to leave just the minimum between the sides.
Donal O’Hare, with four points (three from placed balls), and Kevin McKernan were the Down scorers in the first half.
Murphy, with two frees, Wherity and McFadden each lit up the Donegal side of the scoreboard, while Down goalkeeper Michael Cunnigham denied Neil McGee with a brilliant point blank save.
However, just like they did seven days earlier against Kildare at Croke Park, Donegal improved in the second half. The only difference was on this occasion they pressed on and reeled off seven points without reply.
Murphy (0-04), Kavanagh, who boomed over a massive long range strike, McLoone and Walsh strung together those scores to push Donegal six clear by the 52nd minute.
Down pulled two points back with O’Hare picking off his second point from play in the 65th minutes and midfielder McKernan also raising a white flag, sweeping over a point on the turn. But the horse had bolted and Donegal already had the two league points in the bag.
Daniel McLaughlin, a second half replacement for Patrick McBrearty, brought the curtain down on the scoring with two minutes remaining.
Down introduced Benny Coulter in the second half but not even the former All-Star could revive the Mourne challenge.
Last year’s beaten Ulster finalists also had appeals for a penalty turned down after O’Hare seemed to be tugged as he bore down on goal. His shot at goal was turned away by Anthony Thompson for a '45'.
DONEGAL: Paul Durcan; Ryan McHugh, Neil McGee, Eamon McGee; Declan Walsh (0-01), Leo McLoone (0-01), Anthony Thompson; Rory Kavanagh (0-01), Martin McElhinney; Mark McHugh, Michael Murphy (0-06, 0-04f), Ryan Bradley; Colm McFadden (0-01, 0-01f), Ross Wherity (0-01), Patrick McBrearty;
Subs used: Neil Gallagher for McElhinney (half-time), Dermot Molloy for McBrearty (54), Daniel McLaughlin (0-01) for McFadden (62), Odhran McNialais for N McGee (70).
DOWN: Michael Cunningham; Damian Turley, Daniel McCartan, Ryan Boyle; Ryan Mallon, Aidan Carr, Brendan McArdle; Kalum King, Kevin McKernan (0-02, 0-01f); Keith Quinn, Mark Poland, Paul McComiskey; Conor Laverty, Connaire Harrison, Donal O’Hare (0-05, 0-03f).
Subs used: Peter Turley for McArdle (half-time), Benny Coulter for Harrison (47 mins), Declan Rooney for Mallon (48), Danny Savage for D Turley (55), Conor Goff for King (57).
Referee: Marty Duffy (Sligo)