Nathan Ellington grabbed a brace and Gary Teale was also on the score-sheet for Athletic, with Dickson Etuhu and a late Graham Alexander penalty providing scant consolation for the disappointed home crowd.
It took Roberts just 33 seconds to give himself a dream start to his spell with Wigan.
The striker capitalised from a Teale cross to head home and make himself an instant hit with Athletic's fans.
Preston managed to claw their way back into the game after a dominant spell for the home side.
It was Etuhu who levelled, heading home after a fine delivery from Alexander.
However, Wigan went in at the break with a lead - Ellington putting several misses behind him by converting Nicky Eaden's cross.
Teale then turned goalscorer on 72 smashing home his firts of the season with an unstoppable drive, and Ellington made it four eight minutes later before Alexander converted from the penalty spot to restore a little face to the Preston side.
