David De Gea retained his starting berth but Wayne Rooney lost his role as the Manchester United penalty taker. These were the bulletins from what was the calmest of passages into Sunday's FA Cup fifth round draw as the 11-times winners could hope for.

The tie felt over as early as the 127 seconds United required to strike, though it was not until Javier Hernández's 66th-minute finish that made it 4-0 that the scoreline truly reflected how one-way the traffic had been.

Sir Alex Ferguson said: "It was a good performance. We respected Fulham, as you saw, because we played such a strong side, as we didn't want any slip-ups. This trophy is very important to us this season, we haven't won it for nearly 10 years, so really we need a big performance in it this year."

When the team sheet dropped, United's XI showed six changes, though De Gea was not one of them following criticism of his display at Tottenham Hotspur, and he now moves on to Wednesday's league game here against Southampton.

After his Fulham side went down 2-0 at Manchester City last time out, Martin Jol previewed this encounter by suggesting that United might be got at easier than City.

The Dutchman was alluding to the aerial vulnerability that cost United two points at Spurs, and which allowed West Ham United to take them to a replay in the previous round. Of that 2-2 draw, in which both Hammers goals were headers from high balls, Ferguson wrote in the programme: "It was a reminder that we are hardly going to do well in the Cup if we can't defend better than that."

What United can do is attack in a menacing blur. Under the Old Trafford lights, a mild evening had the best of beginnings for the home congregation when Ferguson's band poured forward and registered from their opening move.

On 40 seconds, Rooney's effort was deflected for a corner. When the Liverpudlian aimed this in from the left, Aaron Hughes used his hand to defend the ball. He was under pressure from Chris Smalling, but that was no excuse. Mark Clattenburg pointed to the spot and, with Rooney having missed 10 penalties for the club, including one in the 1-0 replay win against West Ham, the gaze shifted to see who might step up.

In a moment, it became clear that Rooney had been stood down for Ryan Giggs, who duly slotted to the right of Mark Schwarzer. There had been a hint of the decision in Ferguson's notes when he wrote: "We will really have to up our game in this area."

As entries into this forbidding arena go, conceding after two minutes could not have been much worse for Fulham. Their disarray lingered throughout. Bryan Ruiz sent an errant pass across midfield that found Giggs, Steve Sidwell turned down a couple of blind alleys and, later, having pinned United on their heels, Ruiz's radar was awry as he left the returning Dimitar Berbatov howling in frustration with another poor ball.

Inevitably, the Cottagers' finest moment involved the Bulgarian. Berbatov had received a warm cheer from the United support before kick-off and the control of a pass before playing in Sascha Riether on 32 minutes was plucked straight from the archive of his time here. While the subsequent shot blazed past De Gea's right post, by half-time it was only 1-0 despite United's dominance, and Ferguson may have told his players they should have already killed the tie off.

They should also have had a second penalty when Giggs's 21st-minute pass clearly hit the arm of Damien Duff, who had stuck it out.

If Ferguson ordered his team to be more ruthless, the next seven minutes proved they listened. First, an Anderson pass to Rooney along the inside channel was turned by his right boot on to the left before he blasted home in style reminiscent of the striker's finishing at Euro 2004.

Seconds later, Rooney was the creator. He switched play from the left to Nani on the right. The Portuguese's attempt to find Hernández was repelled and Rooney, who had continued running, threaded the ball to the Mexican, who scored.

"What I'm really pleased about is Chicharito got two today, taking him to 14, Wayne got one and so did Ryan," Ferguson said. "If we have three or four around the 20-goal bracket, we're in business."

For Ferguson, complete satisfaction was thwarted when Hughes completed his topsy-turvy outing by heading home from Giorgos Karagounis's late corner. Rooney was the man detailed to pick up the defender but, as with his spot-kick duties, at least for the time being, he lost this bit of the plot.

For Jol there was relief his side had not been more embarrassed. "It could have been of those nights when they could have scored five, six, or seven."