The Ireland A outside-half had earlier slotted an even bigger penalty attempt from five metres inside his own half but he deflected the praise heaped upon him at the post-match press conference by instead thanking his forward pack for an outstanding all-round display.
"The forwards were unbelievable," said Humphreys after his hat-trick of penalties saw Ulster overturn a 6-0 half-time deficit in driving wind and rain in Northern Ireland.
"Stephen Ferris leads the team so well like that. Everybody was carrying as well. No one was shirking anything. Everybody put their hands up and carried for us and, defensively, the scrum was brilliant.
"I think anybody could have got man of the match. Everybody played so well and that's what you need when you play teams like Biarritz - you need everybody to step up.
"The crowd were great as well. They were really behind us and gave us that extra wee nudge that you need."
As for the 78th-minute strike that snatched a memorable win from the jaws of a draw, Humphreys admitted it was a tremendous feeling to watch Ravenhill erupt all around him.
The former Leicester playmaker insisted he didn't feel the pressure despite the magnitude of the strike - one that leaves Ulster as firm favourites to pick up at least one of the two best runners up spots in the race for quarter-final qualification.
While Biarritz will top Pool 4 if they match Ulster's efforts at Aironi next week, Humphreys and co will travel to Italy knowing they could be about to achieve something no other Ulster side has managed since their title winning campaign of 1999.
"I think the last time I had an opportunity like that was the fourth of fifth year at school, and I missed it," added Humphreys as Ulster moved level with their Basque opponents at the top of Pool 4.
"I didn't really have any doubts - I'd knocked one over from my own 10-metre line in the warm up so I knew all I needed to do was get it on line and the wind would hopefully do the rest.
"I had a bit of a panic when the wind changed direction as I stepped back but fortunately it held straight up.
"The group's not in our hands because of the match points over the two games against Biarritz but we've put ourselves in a position where a good win against Aironi next week should get us qualification of some sort.
"We wanted to deny Biarritz a bonus point but, at 6-6 with two minutes, to go we'll take 9-6 and look to next week.
"We're requiring Bath to do a bit of a job for us and next week won't be easy. Aironi have already beaten Biarritz and we only won over there in the league due to an intercept try, so it's going to be tough.
"But we'll go there full of confidence. That's six wins in eight games now so we know that whenever we've got our full strength team out we're a pretty handy side."