The Italians meanwhile have lost both their matches but complacency has been banned from the Ospreys by Humphreys for Saturday's clash.
He said: "We've played them a few times away now in Europe. It's a tough place to go and win.
"They've got a pretty strong forward pack, they are a good outfit and they have an aggressive scrum, so ours will have to be at its best.
"They have probably one of the most exciting full-backs in the league in Brendan Williams, so they've got a lot of threat.
"We need to be at our very best to make sure we're in a position to challenge for the game."
Ospreys have no new injury concerns, but back-rower Joe Bearman will have to wait to make his debut after failing a fitness test.
And it is in the back row where Humphreys believes the game will be won and lost.
"The shape of our game is something we need to be constantly working on," he added.
"We need to make sure that the boys will always get in the right positions to execute the game plan, which we feel we're very good at.
"The contact area is something we need to be very detailed about. Treviso will come hard at us in that area and try to slow the ball down.
"So as long as we can get quick ball, we will be a dangerous threat."
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