That outcome rarely looked in doubt as we completely dominated proceedings right from the first whistle, with our League Two opponents spending most of the game defending their own penalty box as we enjoyed almost unbroken possession.

That meant it was no more than we deserved when Mason Mount opened the scoring by firing a fine low strike into the bottom corner from 25 yards at the end of one of those long spells of passing.

Any lingering concerns of an upset were effectively put to bed in the last minute of the first half, when two of our German internationals combined as Kai Havertz headed Hakim Ziyech's deep cross down and across goal for Timo Werner to turn in from close range.

By the time Callum Hudson-Odoi latched on to Ziyech's chip over the top to make it 3-0 early in the second half, the game was already effectively over as a contest.

The icing on the cake was provided five minutes from the end, when Havertz added his name to the scoresheet with a towering header from Cesar Azpilicueta's cross.

The selection

Frank Lampard rotated his side to face Morecambe, making six changes from the team that started against Manchester City.

Our head coach had hinted at the chance of rotating his squad for this FA Cup tie and made changes throughout his line-up, starting with the goalkeeper as Kepa Arrizabalaga came in for Edouard Mendy to make his first appearance since our draw with Krasnodar in early December.

In front of him, his fellow Spaniard Cesar Azpilicueta continued as captain, but Emerson Palmieri was at left-back and Toni Rudiger returned to side to partner Kurt Zouma in the centre.

Mason Mount continued in midfield, alongside Kai Havertz and Billy Gilmour, the latter making his first domestic start of the season as he continued his return from injury, having come off the bench in our previous match against Manchester City.

Another young substitute from that game, who scored our goal against City, Callum Hudson-Odoi, was the only change to the front three, as he replaced Christian Pulisic to join Hakim Ziyech and Timo Werner.

Strong start

Morecambe looked determined to try and unsettle their top-flight opposition as they pushed forward right from kick-off and forced Zouma into playing an awkward bouncing back-pass, but Kepa dealt with it calmly. After that brief charge forward, we then immediately pegged the League Two visitors back around their own penalty area, and that is where they would stay.

We were close to creating a great chance to open the scoring in just the third minute, when Hudson-Odoi switched play to Ziyech and the Moroccan floated a curling cross toward the back post, but Werner couldn’t quite get enough on the ball to place his header on target under heavy pressure.

Morecambe’s game plan became evident in those opening exchanges, as they were content to allow us possession while focusing on defending the edge of the box, while attempting to hit us quickly on the counter-attack.

An excellent passing move on the right involving several players almost found space for Mount to let fly from the edge of the box, but when his shot was charged down Emerson hit the rebound first time with power, although it faded wide without worrying goalkeeper Mark Halstead.

There was a brief scare when one Morecambe counter ended with a wayward cross heading towards goal, requiring razor-sharp reactions from Kepa to dive back and smother the ball on the line.

As is often the case against teams defending deep in numbers, it looked like width from our wingers could be key and Hudson-Odoi and Ziyech were both hugging the line and looking to switch play between themselves. Twice that combination resulted in a shooting opportunity for Hudson-Odoi, but as the game passed the 15-minute mark we were still looking to test Halstead for the first time.

However, before the goalkeeper had made a save, he was picking the ball out of the back of the net. After exchanging passes with Emerson out on the left, Hudson-Odoi spotted Mount in acres of space in the middle of the pitch. The midfielder kept things simple when he received the hard low pass, setting himself up with one touch and firing a powerful shot into the bottom corner that left Halstead motionless.

We were soon looking for a second, as Emerson again had a long-range effort blocked and then Rudiger went close with a volley from the resulting corner. He then had another go, which did force Halstead into a low save to his left, but Werner was offside when he attempted to turn in the rebound.

One-way traffic

At times, Morecambe looked to have little answer to our prolonged possession, with all 11 of their players spending long spells camped within 20 yards of their own goal. Their first meaningful spell of possession finally arrived after 25 minutes, following a set-piece in the Chelsea half and long throw into the six-yard box which caused trouble for Havertz and Kepa.

Normal service was soon resumed, though, with Hudson-Odoi and Werner both looking for our second in quick succession as the ball ricocheted around the Morecambe box, but the ball wouldn’t drop fast enough to give either a clear sight of goal.

Although we weren’t making the clear chances we wanted to give us a safety margin before half-time, we were completely dominating possession. Occasionally it seemed our biggest problem might be having too much time on the ball, with a couple of unnecessary pauses and overhit passes frustrating Lampard.

Hudson-Odoi was continuing to cause Morecambe plenty of problems down our left and twice got free to charge into the box with a combination of skill and pace, but both times his low cross was blocked at the near post.

The corner that came about as a result of the second of those provided our best chance to add to our lead so far, as Mount’s delivery found Havertz free on the penalty spot, but the German couldn’t make the contact he wanted as his header skipped wide.

However, a Havertz header played a big part when we did find our second, right on the stroke of half-time. Ziyech curled a looping cross towards him at the back post and our number 29 did well to rise above the defender and head the ball down and across the goal, where Werner was running in to turn it into the net.

We had our two-goal safety net with almost the last action of the first half, and it took us less than four minutes of the second to extend our lead further.

Ziyech picked up the ball deep and spotted Hudson-Odoi breaking the offside trap with a run down the middle. Ziyech chipped a perfectly waited pass over the Morecambe back-line, which Hudson-Odoi brought down well. Halstead did get a hand to his shot, but it wasn’t strong enough to prevent Hudson-Odoi scoring for the second game in a row.

Comfort zone

The Blues were starting to enjoy themselves now with a healthy lead and Ziyech wasn’t far away with an audacious attempt from long range which dipped and swerved just wide of the left-hand post. Havertz was next to go close, when he met Werner’s low cross at the near post, but there was too much pace on the ball for him to direct it goalwards from a tight angle.

With the game increasingly drifting beyond them and Chelsea looking likely to score more the way the game was progressing, Morecambe manager Derek Adams responded by make a triple substitution with half-an-hour remaining.

It did little to arrest our near-continuous possession at this point, though, with Ziyech in particular looking like was starting to enjoy himself. He also seemed determined to get his name on the scoresheet as he let fly from range at every opportunity.

However, he soon left the field as Lampard made his own changes, Ziyech and Werner making way for Olivier Giroud and Christian Pulisic.

Those two were both involved when it took a fine double-save from Halstead to stop us getting a fourth. Good work by Giroud and Mount released Hudson-Odoi in the right channel and the Morecambe keeper reacted well when his low cross was met by Havertz, and he recovered to save again, with a bit of help from his defenders on the line, when Pulisic charged in to hit the rebound on the volley.

Another change from Lampard signalled a change of formation with an opportunity to experiment, as Tammy Abraham came on for Mount to join Giroud in a two-man strike force. That was quickly followed by Fikayo Tomori being introduced for his first appearance since September and teenager Tino Anjorin getting another chance to impress and gain experience.

With much of the fight dropping out of Morecambe and Chelsea knowing the job was done, the game calmed considerably during the last 10 minutes of the match, but there was still time for Havertz to add his name to the scoresheet.

A slick bit of play by Abraham out on the right released Azpilicueta into acres of space and his excellent cross was met by a perfectly timed run from Havertz, who rose above the defence to head the ball down into the bottom corner.

There was still time for Giroud to have his effort at a fifth smothered by the goalkeeper, but as it was we were comfortably into the fourth round of the FA Cup thanks to a 4-0 win with four different goalscorers.

What's next?

We are back in Premier League action with back-to-back away games. First up is the short trip to our west London neighbours Fulham on Friday evening, before travelling to Leicester City the following Tuesday.

Chelsea (4-3-3): Kepa; Azpilicueta (c), Rudiger, Zouma (Tomori 80), Emerson; Mount (Abraham 74), Gilmour, Havertz; Ziyech (Pulisic 68), Werner (Giroud 68), Hudson-Odoi (Anjorin 80)

Unused subs: Caballero, Chilwell, Kovacic, Jorginho

Scorers: Mount 18, Werner 45, Hudson-Odoi 49, Havertz 85

Morecambe (4-2-3-1): Halstead; Cooney (Mellor 62), Knight-Pericval, Davis, Hendrie (Gibson 62); Wildig (c), Songo'o; Slew (O'Sullivan 62), Phillips, Mendes Gomes (Lyons 74); Stockton (McAlinden 85)

Unused subs: Turner, Diagouraga, Kenyon, Leitch-Smith

Referee: Darren England