Martyn Waghorn, who had been on loan at the DW Stadium, broke the deadlock for the hosts just one day after signing permanently.
The hosts passed the ball well but it was Leeds who had the best of the early exchanges, missing a couple of half-chances before almost conceding themselves when Perch connected with Jordi Gomez's cross but headed wide.
The former Newcastle United man continued to be involved, being penalised for another elbow but escaping this time without a second yellow card.
Wigan began to relax after that, passing the ball well and posing a threat through Gomez in particular. Their pressure told on 33 minutes when a good advantage by the referee allowed Waghorn collect the ball after a foul, and curl it into the bottom corner.
Leeds responded well to going behind but failed to really threaten the home defence before the break.