The Welsh side stayed second in the league table but had to dig very deep in the second half to preserve their 19-13 win against the Red Army.
With 19 players missing on international duty it was a miracle that head coach Scott Johnson could even put a side out at the Liberty Stadium on Saturday.
But Humphreys never doubted his side's ability to grind out a result, regardless of the individuals selected.
"It's been a fantastic effort by this group of boys," he said.
"The competitiveness and spirit that they have is first class and we are delighted with the effort that was shown out there.
"We've always prided ourselves that we are a region that develops players and we are delighted when they go and play international rugby, but the boys that don't go are as competitive, and they display the culture and the values that we want from Ospreys players.
"There were some testing times out there, particularly those last few minutes, but we're gaining a reputation as a team that can win close games, that can close out tight games and can win narrowly and we showed that today."
"Everybody who played out there made a massive contribution. We were under no illusions at the size of the task, but we back ourselves here, we back the Ospreys team no matter what it is, and I couldn't be prouder of this group of players."
And with a whole host of internationals set to return for their upcoming Heineken Cup double header with Saracens Humphreys conceded they have a tough task in picking their XV during the week.
"We always have selection problems, so this week is nothing different," he added.
"How do you reward two groups of players? How do you reward the ones who have performed really well these last two weeks, but not penalise players for going away to play for their country? It's a headache that we've always had."
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