Humphreys admitted he was delighted with the performance, which saw Irish fail to collect a losing bonus point, but claimed there was more to come as his side was only just hitting their stride.
"We are a team, it just takes us a little while to come back together and click. Generally it sort of comes around Europe time," said Humphreys.
"To get a home win and Irish get nothing, we'd have settled for that before the game. I thought we improved from last week in how we closed the game out. We were very smart in terms of that.
"Our defence is outstanding at the moment. It's something that these boys enjoy doing. We are going in the right direction and we're not leaking points."
Welsh counterparts Cardiff Blues had a less enjoyable evening, going down 27-20 away to Castres, although they did collect a potentially crucial bonus point.
Castres held a commanding 27-6 half-time advantage thanks to tries from Vincent Inigo and Marc Andreu and Romain Teulet's kicking and a Seremaia Baikeinuku penalty.
But a Ma'ama Molitika try restored Welsh spirits, aided by the kicking of Ceri Sweeney and Ben Blair, before a last-minute Scott Andrews effort secured a point for the Blues.