The Connacht fly half booted five penalties, including two from inside his own half to set up the win over the Ospreys who let slip a 10-3 half time lead.
It had been McHugh, however, who had erred to allow the visitors to score the only try of the game. His loose grubber kick was fielded by Justin Marshall who was able to collect on his way to the try line.
The men from the west of Ireland were able to provide a gritty second half performance which left the test stars of the Ospreys reeling as McHugh hit four second half penalties including one deep into injury time which secured the points.
Ospreys Head Coach, Lyn Jones refered to the outcome of the match as a ‘thunderbolt’, and vowed to put the performance behind the Ospreys as they concentrate on their forthcoming midweek derby with the Blues.