The Swans dropped games to fellow top-four sides Collingwood and Hawthorn, and in-form reigning premiers Geelong in the past four weeks.
It's been a less than ideal preparation for Saturday's qualifying final against Adelaide at AAMI Stadium.
But John Longmire's charges were competitive to varying degrees in all three matches, even in Saturday's 34-point loss to the Cats when they played an impressive first half.
Their multiple finals dress rehearsals are in sharp contrast to the Crows' path to the weekend's showdown.
Adelaide played just one top-eight side in their final five games, Fremantle, who they beat by 28 points on August 11.
Mumford was upbeat his team's testing run towards September would hold them in good stead on the weekend.
"We know our best stands up against the best and if we can play four quarters of consistent, solid footy, we know that will get us across the line," Mumford said at the Swans' recovery on Sunday.
"It's good to be able to test yourself and see what areas you do need to improve on, coming into the finals.
"It's been a great thing for us, we've played the top sides and know how they'll play and it's been finals-like atmosphere and intensity in those games.
"We definitely know where we're at and what we've got to work on and hopefully we can do that this week and come out firing."
Mumford expected defender Nick Smith (hamstring) and key forward Sam Reid (glute strain), both absent from the loss in Geelong, would be fit to take on the Crows.
"From what they've both said to me today, they should be right to go," he said.
"There'll be a couple of unlucky people, but you've got to play the best side."
Adelaide defeated the Swans by five points in the two sides' only meeting this season, a game best known for the quad injury that made Adam Goodes miss five matches.
Mumford was sidelined with a back infection for that May 5 SCG clash, and had few memories of the match.
But the 26-year-old knew Saturday's clash - and the rest of September - would be more exacting.
"Finals footy, the intensity goes up again and we're going to have to lift another level again - young and old," he said.
