They were seldom troubled by a tidy, hard-working Oldham side who struggled to create clear-cut scoring chances.
Kevin Blackwell made eight changes from the team that beat Wolves, including a debut for Rui Marques, a first start for Jonathon Douglas and a rare chance to shine for Stephen Crainey and Danny Pugh.
Leeds introduced new £1.1million striker Richard Creswell to the fans before the game, but it was one of the five he is hoping to displace who had the faithful on their feet as Leeds wrapped up the game with two goals in four minutes midway through the first half.
The much maligned Ricketts lived up to the praise in Blackwell's programme notes when he climbed to flick on a long punt forward, then raced on to the ball and fired home from a difficult angle.
It was his first goal since he opened his Leeds account in this competition against Swindon last September.
Oldham had started brightly, Andy Liddell going close with a 25-yard free-kick in the fourth minute and Guy Branston's flicked header from a corner forcing a goal-line block from Richardson.
But with Gylfi Einarsson bossing midfield, Leeds started to get a grip on the game once Ricketts' goal went in and four minutes later a pull-back from the by-line found Richardson steaming in to rocket the ball past Chris Day.
The second half was something of a damp squib. Leeds stopped passing the ball and though they put in plenty of effort, Oldham failed to create clear-cut chances.
Their best efforts came from long range with Richie Wellens just wide and Marc Tierney also failing to hit the target from 25 yards.
Leeds' best chance came from David Healy on the six-yard line but Branston flung his body in the way and got in a block.