LONDON -- The celebrations revealed more than Chelsea's performance did. For almost all of Tuesday night's Carabao Cup quarterfinal, the Blues were a familiar sight: errant at the back, ponderous in possession and largely toothless in attack.

Trailing to Callum Wilson's 16th-minute strike -- a product of some calamitous defending -- Chelsea were drifting out of a winnable competition and staring down the barrel of spending 1 billion in 18 months and only having the FA Cup left to play for.

- Stream on ESPN+: LaLiga, Bundesliga & more (U.S.)

Enter Kieran Trippier. The 33-year-old has been a hugely reliable performer for Newcastle and England but he is in wretched form and in the space of a few minutes, he gifted Mykhailo Mudryk his stoppage-time equaliser and then missed in the penalty shootout as this 1-1 draw ended in a 4-2 win which takes Chelsea through to the semifinals.

Pochettino greeted the equaliser with raucous celebrations on the touchline perhaps only surpassed by the moment Matt Ritchie saw his spot-kick saved by Djordje Petrovic to send the home side into the last four. Bear hugs and screams of "vamos" followed as Chelsea's players embarked on what has become something of a customary lap of appreciation but never with this vigour, Pochettino departing early while shaking his arms to Gala's "Freed From Desire."

This has been a difficult season for everyone at Stamford Bridge and shared experiences such as this can have a galvanising effect on a squad still getting to know each other after being thrown together in the Todd Boehly/Clearlake Capital era.

"It is important, these type of games, [for] the way we achieved going through to the semifinals," said Pochettino. "Like when it is important when you don't play well like Everton and Newcastle away from home [losing both Premier League games], is to realise in which areas we need to improve.

"I think both are really important, we feel for this group in the way we want to evolve and our ideas.

"Of course, I am so pleased because when you see the whole squad, players that weren't involved in the game, players that were injured but they want to share the happiness in the middle of the pitch, it looks like we are a healthy group of players that only need time.

"We must guide them, create a platform for them, and help them improve every day. Of course, with time I think we are going to create a very good team that can compete, increase the competition, and be in the place that Chelsea should be."

That place is still a long way off. This was a modest stepping stone in terms of Chelsea's overall display. Newcastle were missing 10 players and looked fatigued from a gruelling schedule featuring their first Champions League group stage campaign in 21 years. Chelsea counted nine absentees themselves and a 10th after Enzo Fernández walked off 32 minutes into the game due to sickness.

They could have lost Moisés Caicedo much earlier -- in the second minute -- after a bad tackle on Anthony Gordon was only punished by a yellow card but with VAR not in use during this competition, the Ecuadorian escaped further scrutiny. Conor Gallagher hit the crossbar after seven minutes and a promising Chelsea start was undone by a farcical piece of defending in which Caicedo and Thiago Silva were at fault before Benoit Badiashile spared both their blushes by tripping over the ball to allow Wilson a free shot at goal.

Chelsea laboured in pursuit of parity. With 21 minutes remaining, Pochettino turned to 52 million signing Christopher Nkunku for his debut, delayed by a knee injury sustained in preseason. These were difficult circumstances to throw him in but Pochettino had little alternative given silverware was slipping from their grasp. And just when all appeared lost, substitute Malo Gusto fired in a cross which Trippier chose to head aimlessly back into a central area, allowing Mudryk to pounce.

Cole Palmer, Gallagher, Nkunku, and Mudryk scored while Trippier and Richie missed and suddenly Chelsea could look forward to the prospect of a two-legged semifinal in January.

Pochettino can now take the positives from what threatened to be a chastening night. The trophy is not in their grasp -- Liverpool remain clear favourites -- but the absence of Manchester City, Arsenal, Manchester United, Aston Villa, and others from the last four makes it feel within their reach.

On an individual level, Nkunku converted his penalty, Petrovic saved one to boost his efforts in proving an able deputy for the injured Robert Sánchez and the much-maligned Mudryk registered his third Chelsea goal.

"We are talking about players that are young, players that arrived and suffered an injury like Christoph," said Pochettino. "Now they need the competition, they need game-time to start to perform. The expectation is to see the best Nkunku. We need time for him to perform in the way we expect. One thing is to be available, another is to perform in the way we expect."

Chelsea are still not performing in the way many expect but it is extremely useful for a manager trying to impose himself like Pochettino that silverware remains a distinct possibility.