Cesc Fabregas was the hero as we progressed to the quarter-finals of the Carabao Cup courtesy of a 3-2 win over Derby County on a night when club legend Frank Lampard returned to Stamford Bridge.
All five goals arrived in an action-packed first half, with the Blues leading twice through own-goals scored by Fikayo Tomori and Richard
Keogh, but Derby hitting back quickly on each occasion.
It was Fabregas who gave us the advantage for the third time four minutes before the break, pouncing on a loose ball inside the box to fire home what proved to be the winning goal, although there were chances at both ends in the second half with Alvaro Morata going close with a header while David Nugent struck the post for Derby late on.
Maurizio Sarri made eight changes to the side which beat Burnley on Sunday, with only N’Golo Kante, Willian and Morata retaining their places.
There were wholesale changes to the defensive unit as Willy Caballero replaced Kepa and Gary Cahill and Andreas Christensen formed a partnership at the heart of the back four, while Mateo Kovacic and Fabregas were also handed starts in midfield.
Ruben Loftus-Cheek, meanwhile, a substitute and scorer at Turf Moor, started on the right-hand side of the attacking trio.
For Derby, Chelsea loanees Tomori and Mason Mount, who had been given special dispensation to play by the Blues, both started.
Prior to kick-off there was a minute’s applause to remember Ken Shellito, our former player and manager who sadly passed away at the age of 78, as well as those who lost their lives in the helicopter crash in Leicester on Saturday night, with all inside Stamford Bridge paying due respect.
It was a bright start by the Blues as we looked to get men forward early on and after an Emerson Palmieri cross had been collected by Scott Carson, Kovacic cut inside and fired just wide of the near post.
As the five-minute mark approached, and with our next attack, we took the lead. Loftus-Cheek intelligently played the ball into the path of Davide Zappacosta and as the Italian delivered across the face of goal, Tomori diverted the ball into the back of his own net.
It was the perfect start for Chelsea, but our lead would last only a matter of minutes as the visitors hit back almost immediately.
Cahill played the ball out from the back but as Derby retrieved possession Tom Huddlestone picked out the run of Jack Marriott who advanced towards goal and drilled his strike into the bottom corner.
Seven minutes after drawing level Derby should have taken the lead when Marriott turned provider and put Martyn Waghorn clean through on goal, but as he raced into the box the forward appeared to lose his balance and rolled a tame effort straight into the arms of Caballero.
It was Derby who were looking the bigger threat going forward, but we restored our advantage just after the 20-minute mark with a goal which followed a similar pattern to our first.
Once again Loftus-Cheek found Zappacosta, and once again the defender’s cross was diverted past Derby goalkeeper Carson by one of his own team-mates, on this occasion captain Keogh.
Loftus-Cheek dragged a left-footed drive just wide moments later and Willian fizzed a strike over the bar, but just like earlier in the game the visitors were soon back on level terms.
From a throw-in deep inside our half the ball was worked inside to Mount, who rolled the ball across the face of goal where Waghorn stole in to force it over the line and make it 2-2.
Most of our good work during the first half had been down the right-hand side, with Zappacosta experiencing plenty of joy up against Scott Malone, and Morata was unfortunate not to profit from another inviting cross by the defender, the Spaniard eventually crowded out as he brought the ball under control.
Five minutes before the break, though, we were back in front as Loftus-Cheek pulled the ball back into the path of Zappacosta, and despite the fact he was unable to bring it under control, the loose ball ran into the path of Cesc Fabregas who crashed his strike into the back of the net to make it 3-2.
There was no further goalmouth action before the half-time whistle sounded and we headed in with a slender lead after a lively opening 45 minutes.
Loftus-Cheek worked himself into a couple of dangerous positions early in the second half although there was nobody able to profit from his teasing deliveries across the face of goal, and Carson then produced a fine save to deny Cahill, whose header appeared destined for the bottom corner.
The best chance of the second half until that point, however, went Derby's way as Huddlestone released Marriott. The forward raced through and fired towards goal from an angle, with Caballero getting a strong enough hand behind it to deflect the ball up and over the bar.
David Luiz was introduced at the expense of Christensen midway through the half and that change was quickly followed by another as Pedro replaced Loftus-Cheek.
Mount was using the ball well in the final third and the midfielder flashed a right-footed drive inches past Caballero's right-hand post as the visitors attempted to find a way back into the game, and as the contest entered its final 15 minutes there was still plenty of work for us to do.
Zappacosta, who had been a real threat in an attacking sense throughout, picked out Morata with a superb delivery from out on the right but the striker lost the flight of the ball as it dropped over the covering defender's head and the chance was gone.
Moments later, however, Morata connected brilliantly from a Willian corner and was only denied by a superb Carson save from point-blank range.
The visitors continued to push for a leveller and it almost arrived when Keogh, up from the back, latched on to a ball from deep, only to be denied by the quick thinking of Caballero, who had raced off his line quickly in order to narrow the angle. The Argentine then saved low down to his right as Mount went for goal from distance.
With two minutes left on the clock Derby pushed forward again and as the ball found its way to Nugent, his angled drive came back off the foot of the post. It was a lucky let-off and the Chelsea fans inside the stadium were delighted to see the ball bounce back up into the arms of Caballero.
As the final whistle sounded, with our passage secure, the name of Frank Lampard rang out around Stamford Bridge.
Our all-time highest scorer, and assistant Jody Morris, had been given the reception they deserved by the Stamford Bridge faithful, but more importantly we were through to the last eight with our unbeaten record still intact.
All in all, a good night's work for Sarri's side, who welcome Crystal Palace to the Bridge on Sunday in the Premier League.
Chelsea (4-3-3): Caballero; Zappacosta (Azpilicueta 77), Cahill (c), Christensen (David Luiz 64), Emerson; Kante, Fabregas, Kovacic; Loftus-Cheek (Pedro 68), Morata, Willian.
Unused subs: Bulka, Drinkwater, Barkley, Hudson-Odoi.
Scorers Tomori OG 5, Keogh OG 20, Fabregas 40
Booked Emerson 84
Derby County (4-3-3): Carson; Bogle, Tomori, Keogh (c), Malone (Forsyth 81); Mount, Huddlestone, Wilson (Nugent 81); Waghorn (Bennett 61), Lawrence, Marriott.
Unused subs: Roos, Davies, Johnson, Holmes.
Scorers Marriott 9, Waghorn 27
Referee Jonathan Moss.