The impressive Whittaker opened the scoring for Rangers
Trophy holders Rangers eased into the semi-finals of the Scottish Cup with a comfortable victory over Hamilton.
Steven Whittaker opened the scoring with a fine run and shot, only for Rocco Quinn's strike to level matters.
Kyle Lafferty slotted in a cool, close-range finish and Aaron Niguez converted a retaken penalty before half-time.
Steve Davis evaded a number of weak challenges before picking his spot with aplomb and Lafferty finished off a neat passing move for the fifth goal.
The Ibrox side turned in a dominant display after their surprise midweek defeat to Inverness and their cause was aided by a series of injuries picked up by the visitors, who played out most of the second half with 10 men.
Rangers made a menacing start, with striker Kenny Miller looking sprightly, while Hamilton were forced into an early change as full-back Brian Easton limped off after eight minutes.
The visitors were still readjusting their formation when they fell behind to an outstanding solo goal from Whittaker.
The former Hibs defender cut in from the right flank and danced past two challenges before drilling a low shot in at Cerny's near post.
Hamilton had shown little attacking intent but found themselves level on 26 minutes, when Gers keeper Allan McGregor failed to collect a cross from James McCarthy in a congested penalty box and Quinn drove the loose ball into the net from 14 yards.
However, the Accies joy was short-lived and Rangers restored their lead nine minutes later.
Whittaker whipped in a cross which was deftly knocked into the path of Lafferty by Miller and the Northern Ireland striker showed a fine touch to round Cerny and slot home.
Hamilton had to reshuffle once again as Mark McLaughlin was forced out of the action with a head knock and replaced by Chris Swailes, who immediately conceded a penalty by chopping Miller down.
Aaron stepped up and saw his effort blocked by Cerny but referee Iain Brines ordered the penalty to be retaken on the advice of the linesman watching the goal-line and the Spaniard converted his second attempt from the spot.
Aaron scored his first goal at Ibrox from the penalty spot
Hamilton used their third and final substitute at the interval; forward Derek Lyle replacing defender David Elebert.
But any chance of a dramatic comeback was quickly snuffed out when Davis waltzed past a number of static opponents to slide a composed finish beyond Cerny.
And there was a further blow for Accies manager Billy Reid, since his team were soon depleted after an injury to striker Richard Offiong.
Rangers were content to knock the ball around in a leisurely manner and were almost caught out by McCarthy but the teenager's promising thrust from midfield was brought to a halt by David Weir and Madjid Bougherra on the edge of the penalty box.
Quinn squandered a great chance to double his tally, toe-poking a shot on the stretch straight at McGregor and the home keeper was alert to clutch Paul McGowan's attempted lob from the rebound.
A slick passing move led to Rangers' fifth goal on 81 minutes, with Barry Ferguson and Whittaker combining expertly to set up Lafferty, who slipped a low shot under Cerny from 10 yards.
Rangers assistant manager Ally McCoist:
"I felt the most important period of the entire game would be the first ten minutes of the second half.
"Thankfully, we got the fourth goal, which effectively killed the game.
"You'd need to be a cruel man not to feel something for Accies today. They have been a credit to their manager and their coaching staff. I'm sure they'll bounce back.
"I hope the injuries aren't long-term and that they can get their boys back. They don't have the biggest squad in the world. So far in the league campaign they have been fantastic and good luck to them.
"I'd like to have seen Aaron Niguez get on the ball a bit more, be a bit quicker.
"I'm delighted for (Steven) Whittaker, I thought he performed well. (Kyle) Lafferty got another two goals and it was good to have Pedro (Mendes) back as well."
Hamilton manager Billy Reid:
"It was one of those days, we were never going to win the game - nothing went right from us, right from the off.
"We're under pressure with injuries at the moment, so we were forced into four changes and played with 10 men for the last 30 minutes.
"But I have no complaints. Even with 10 men we tried to get on the ball and pass it.
"It ask the guys to take responsibility, and they do it in abundance.
"But I have to say Rangers deserved to win, it was one of those days when nothing went right for us."
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