Chelsea held off League One leaders Cardiff City to secure their place in the EFL Cup semi-finals with a hard-fought and absorbing win in south Wales.

Roared on by a fervent capacity crowd at Cardiff City Stadium, the home side impressed in and out of possession as they contained their Premier League opponents and showed flashes of their own attacking threat in a goalless first half.

Chelsea boss Enzo Maresca had changed his entire team from Saturday's Premier League victory over Everton, which had been overshadowed by his post-match comment that the preceding 48 hours had been the "worst" of his tenure.

The Club World Cup champions' underwhelming first-half display will have done nothing to improve the Italian's mood, so he made two half-time substitutions and it was one of those – Alejandro Garnacho – who fired them in front after Cardiff centre-back Dylan Lawlor had given the ball away.

Brian Barry-Murphy's side responded strongly and equalised as David Turnbull headed in superbly from Perry Ng's inviting cross to prompt deafening celebrations.

They were short-lived, however, as another Chelsea substitute, Pedro Neto, restored their lead with firm a low drive which took a deflection on its way in.

Garnacho then added a third in added time to make sure of victory.

Those goals momentarily deflated the raucous atmosphere, but Cardiff can take great encouragement from the way they equipped themselves against elite opposition as they turn attentions back to their bid to make an instant return to the Championship.

As for Chelsea, this was a welcome result – if an unconvincing display – after a difficult few days for Maresca.

They will discover their semi-final opponents when the draw is made on Wednesday.

Chelsea analysis: Maresca's 'worst' week picks up

Maresca had come under scrutiny after his unexpected, somewhat cryptic remark had dominated the aftermath of Chelsea's win against Everton as well as the build-up to this encounter, with the Italian clearly irritated when he was repeatedly asked to clarify his comment during a pre-match news conference on Monday.

That was a distraction, but ultimately not enough to derail Chelsea here.

Even with 11 changes from the Everton game, Maresca was able to name a strong line-up with the likes of £100m midfielder Moises Caicedo recalled, while the bench was worth close to £400m.

Unimpressed by a first half in which his side barely troubled their lower-league opponents, the head coach brought on Garnacho and Joao Pedro at the interval.

Their introduction immediately added a purpose and sharpness the Chelsea attack had been lacking, with Garnacho forcing Cardiff goalkeeper Nathan Trott into a fine save.

The former Manchester United winger was more clinical with his next effort, finishing well after being put through by Facundo Buonanotte, who had been gifted possession by Lawlor's loose pass.

Chelsea might have worried an upset was in the offing when Cardiff levelled but, to their credit, the London club responded calmly as Neto powered a shot into the bottom corner, via a deflection off Joel Bagan's heel.

Garnacho's late second arguably flattered Chelsea, but they were worthy winners as they went a step closer to winning this trophy for the first time in 10 years.

Cardiff analysis: League One high-flyers impress

For anyone who had not watched Cardiff in League One this season, this might have been quite a surprise.

Gone is the robust, direct style of play favoured by Neil Warnock, Mick McCarthy and other previous managers.

That has been replaced by a freewheeling, possession-based brand of attacking football carried out by a young team brimming with Bluebirds academy graduates.

Admittedly, Cardiff are playing in the third tier of English football for the first time in more than two decades, but this season has been unusually joyous for a club who had lost their way in the Championship.

Having seen off Premier League Burnley and ambitious fellow Welsh side Wrexham in previous rounds of the EFL Cup, this was a first chance for Barry-Murphy's charges to test themselves against a real heavyweight.

They rose to the challenge admirably, impressing out of possession with positional discipline and coordinated pressing, while also causing their illustrious opponents problems.

Callum Robinson and Turnbull saw early efforts saved, while Isaak Davies was a nuisance on the left wing and his deflected low cross had Chelsea keeper Filip Jorgensen scrambling.

The Bluebirds' endeavour was rewarded when Ng cut in from the right and arced a beautiful left-footed cross for Turnbull, who shifted his bodyweight and headed smartly into the net to spark wild celebrations.

The home crowd were baying for more at that stage and, although the giant-killing was not to be, this was a performance full of skill as much as heart to enhance the reputations of every Cardiff player and their boss, Barry-Murphy.