Saturday's defeat at Bury left the Bees three points behind Northampton in the battle to stay in League Two after their upward momentum was halted by the departure of manager Martin Allen for Notts County.
Grazioli took the reins for the trip to Gigg Lane and will now be able to call on the help of former Northern Ireland boss Sanchez.
He said: "I've come in to help Giuliano, who is a football acquaintance, with the big task of helping Barnet off the bottom rungs of League Two."
Barnet travel to Gillingham on Saturday, hours after the Cobblers host Northampton at Sixfields.