Gary Caldwell had to clear when Al-Habsi spilled a van Persie flag-kick with Jonny Evans and Giggs trying to profit and the keeper also dealt with a Rafael drive rather unconvincingly, even if he did parry it to safety.
With 35 minutes on the clock, the breakthrough duly arrived courtesy of the ever-alert Hernandez. Rafael won a header to find Tom Cleverley and the former Wigan loanee helped the ball down the line to Evans, who produced a measured cut-back. Although Patrice Evra miskicked, he forced a one-handed save out of Al-Habsi at the second attempt and Hernandez pounced to convert the rebound.
A second goal effectively killed off the match as a contest before the interval as Michael Carrick's pass found its way past two defenders to allow Hernandez plenty of space to assess his options. The Mexican decided to pass to his strike partner and van Persie did not disappoint, sitting Ivan Ramis on his backside with a dummy, before guiding a right-footed finish wide of the motionless Al-Habsi for a strike of pure genius.
There was still time for Hernandez to find the net again before the half-time whistle, following some stunning work in midfield by van Persie, but the lively forward was again rightly flagged offside when prodding the ball under Al-Habsi.