Ciaran Whelan said lacklustre Cavan barely tested Donegal in their Ulster SFC tussle in Ballybofey, but was impressed with how Declan Bonner's men started their summer in Ballybofey.
Cavan wilted in the May sunshine as their hosts powered to a 2-20 to 1-15 success.
There was only four points in it at the break, but Donegal pulled away in the second half and were full value for a handsome win.
"They were impressive," Whelan said on The Sunday Game. "They done what they had to do. I'd be worried about how flat Cavan were though.
"You're trying to evaluate how good were Donegal because Cavan lacked intensity. It had the sense of a challenge game. It didn't feel like an Ulster Championship (game).
"The thing about Donegal is they have potential. They've good quality players. To put up 2-20 was a big big score for them.
Sean Cavanagh agreed that a poor Breffni performance made it hard to measure Donegal's display.
While Donegal set up a quarter-final showdown with Derry, Cavan have some soul searching to do.
"They didn't turn up," Cavanagh said. "You associate with Cavan with tough, committed hard-hitting players. There weren't that many challenges over the 70 minutes from Cavan players.
"Ballybofey is a really difficult place to play, I found that out on more than one occasion, but the space and freedom Donegal players got was just too much."
