Our high press caused Barnsley problems all night, and that is how the breakthrough arrived 20 minutes in, when Tammy Abraham dispossessed the defence on the edge of the back finished ruthlessly.

Kai Havertz added his first goal in a Chelsea shirt after Abraham had dummied Mason Mount’s pass, but it was after the half-time break that the floodgates opened.

First Havertz won possession just outside the box for Barkley to stride forward and finish powerfully, before the German got his second from close range when Abraham flicked on Mount’s low cross.

Havertz then got his third and Chelsea’s sixth of the night when he beat the goalkeeper to Abraham’s ball in behind, allowing him to tap into an empty net, and then two substitutes combined to make it six when Olivier Giroud headed in Ben Chilwell’s cross.

The selection

The big news from Frank Lampard’s team sheet was a debut from the start for Thiago Silva at the centre of our defence, with the Brazilian partnering Fikayo Tomori in a much-changed side from our Premier League defeat to Liverpool at the weekend.

Willy Caballero comes in as goalkeeper as expected for the Carabao Cup, with Cesar Azpilicueta returning as captain on the right of the defence and Emerson on the left.

In midfield, Mateo Kovacic kept his place to make his 100th appearance for Chelsea in all competitions, alongside Ross Barkley in a deep pairing. Ahead of them, Kai Havertz moved into the central role behind the striker, flanked by Mason Mount on the left and Callum Hudson-Odoi on the right.

Tammy Abraham made his first start of the season as the central striker, while new signing Ben Chilwell and young goalkeeper Nathan Baxter were named on the bench for the first time.

Barnsley made five changes themselves from the team which lost to Reading at the weekend, although two of them were due to suspension after a double sending off in that match. Among the new faces was former Chelsea goalkeeper Brad Collins.

Bright start

It took us less than a minute to test the Chelsea Academy graduate Collins in the Barnsley goal and it owed much to the movement of Havertz. The German did well to find space between the lines and create a two-on-one situation with the visiting centre-backs with his first touch. His second released Hudson-Odoi to his right, but Collins came out quickly and made himself big to block the winger’s shot.

Hudson-Odoi was finding space out on the right and looked dangerous again after being found well by Barkley, but Barnsley got numbers back quickly enough smother the threat. The visitors were making the some early forays into attacking territory themselves, though, requiring a couple of strong blocks, most notably from Azpilicueta on the 10-minute mark, and then Caballero was called into action to tip Cauley Woodrow’s dipping shot over the bar.

Havertz had a chance himself from close range, after Abraham had burst free down the middle and combined well with Mount to play in the German, but he couldn’t get power in his shot, off balance and under pressure, meaning it was an easy save for Collins.

We did have the ball in the back of the net a minute later, though, when Abraham’s work rate paid off. He pressed the centre-backs to capitalise on some slack passing at the back by Barnsley, nicking the ball away on the edge of the box and calmly slotting the ball into the bottom right-corner.

The Championship side tried to respond instantly, but again Caballero was equal to their effort from range, saving a powerful shot comfortably low to his left.

Havertz off the mark

Mount was inches away from extending our lead after more good work from Havertz, who drove infield from the lift and slid a perfectly weighted pass through the Barnsley defence, but our number 19’s low finish was just the wrong side of the near post.

Havertz had looked lively as we approached the half-hour mark, and was soon celebrating his first goal in a Chelsea shirt. Mount found space wide on the left and his dangerous-looking pass towards the box was cleverly dummied by Abraham, who had noticed Havertz making a late run behind him. There was no hint of nerves from the man enjoying his first experience of English cup football, who controlled the ball deftly with his right foot before rolling it into the back of the net with his left.

That goal was immediately followed by a brief but heavy downpour, although the rain didn’t seem to dampen Barnsley’s enthusiasm as they again called Caballero into action from range, but the Argentine wasn’t troubled.

On the stroke of half-time, shortly after Barnsley had again forced a save from Caballero, the referee was given a big decision to make, when Abraham beat Collins to Barkley’s looping pass over the top and was floored by the goalkeeper just outside the box. As it was, Darren Bond decided a free-kick and a yellow card was punishment enough, and Mount’s shot from the set-piece was too high to trouble Collins.

Coming out firing

Barnsley manager Gerhard Struber shuffled his pack during the break, replacing former Fulham forward Woodrow with Luke Thomas. However, it didn’t have the desired effect as began the second half looking more comfortable in possession than ever before, and less than five minutes after the restart we had made it 3-0.

Again, the goal allowed plenty to Havertz and the pressure we were putting the Barnsley defenders under when they had the ball. This time it was Havertz who caught them in possession with a fine sliding tackle, allowing Barkley to pick up the loose ball and stride forward a few yards into the box before striking low past Collins.

By the time another five minutes had passed we had another, and events were starting to follow a common theme. Mount won the ball in advanced position wide on the left and his quick low cross was flicked on by Abraham into the path of Havertz, who again made things look simple as he applied the calm finish.

That prompted Barnsley to use their two remaining substitutes, but in truth at 4-0 the games was looking all but over with a little over half-an-hour remaining. That feeling was reinforced when Thiago Silva made way for Kurt Zouma after a solid hour's work on the Brazilian's debut.

Almost before Barnsley had time to regroup they had conceded again, and Havertz had completed his hat-trick. Abraham did brilliantly the volley Azpilicueta’s pass around the corner to release Havertz and when he beat Collins to the ball again it bounced through the keepers legs and Havertz with a simple finish into the open net.

It was Havertz's last involvement in the game, as before the match restarted he made way to allow Ben Chilwell to come on for his own Blues debut, slotting in at left-back as Emerson moved into midfield.

Lampard’s final substitution was to send on Olivier Giroud for Abraham and the Frenchman was unlucky not to get an assist to his name, when he was fed in the right channel by Mount and squared the ball across goal, but Barkley couldn’t apply the finish at the back post.

Azpilicueta was inches away from heading in our sixth at the back post from Hudson-Odoi’s angled cross, but it didn’t take much longer for the next goal to come. It was the new boy Chilwell who created it as he curled an excellent ball in from the left, with Giroud in acres of space to stoop low and head in from around the penalty spot.

Good night all around

Lampard would have been very happy with his team’s work on a wet night. Six goals – three of them for a player opening his account for the club – a clean sheet, two solid debuts from a couple more of our new signings and plenty of effort from his players both on and off the ball. Plus, of course, our place in the fourth round of the Carabao Cup well earned.

What’s next?

We are back in Premier League action late on Saturday afternoon, when we travel to The Hawthorns to face newly promoted West Bromwich Albion.

Chelsea (4-2-3-1): Caballero; Azpilicueta (c), Tomori, Thiago Silva (Zouma 61), Emerson; Barkley, Kovacic; Hudson-Odoi, Havertz (Chilwell 66), Mount; Abraham (Giroud 72)Unused subs: Baxter, James, Jorginho, WernerScorers: Abraham 19, Havertz 29, 54, 65, Barkley 49, Giroud 83

Barnsley (4-2-3-1): Collins; Ludewig, Sollbauer, Halme, Williams; Styles, Ritzmaier (Oduor 57); Mowatt, Woodrow (Thomas h-t), Frieser (Chaplin 57); SchmidtUnused subs: Moon, Walton, Simoes, AdeboyejoBooked: Collins 45

Referee: Darren Bond