A penalty from Eamon Buckley in the 8th minute had Young Munster in front, a lead they held until Humphrey's intervened in the second half.
In Division Two the top two places remain unchanged after leaders Belfast Harlequins and second placed Barnhall both won. Harlequins increased thier lead over Barnhall to four points thanks to a maximum haul in a 62-0 drubbing of Ballynhinch at Balymacarn Park.
Just down the road at Chambers Park, Barnhall came away with four points following their 12-9 win over Portadown.
Old Wesley took over the leadership of Division Three following their 10-6 win over Ballina in Donnybrook. A try from Jamie Sharp, converted by John Lynch who also kicked a penalty gave Old Wesley a ten point interval lead and although Ballina came back strongly in the second half, the Jim Lowry coached home side held on for a well deserved victory.