The Blues overcame Newcastle United in a nail-biting penalty shootout to reach the final four, while Michael Carrick's troops put three past Port Vale without reply in the quarter-finals.
Match preview
Despite eventually succumbing to Aston Villa's superiority in Saturday evening's FA Cup tie, Middlesbrough boss Carrick cut a relatively upbeat figure while conducting his post-match media duties, and rightly so after watching his charges go toe-to-toe with the unfancied Premier League title challengers.
Boro - who are currently entrenched in the middle of the Championship rankings - held out for 87 minutes against the Lions, who are under the tutelage of serial cup specialist Unai Emery, but a speculative Matty Cash strike, which took a major deflection off of Emmanuel Latte Lath, proved to be their undoing.
While there may have been a few glum expressions around the Riverside as Cash's effort sneaked into the bottom corner, Middlesbrough could certainly reflect on the positives from that one-goal defeat, even if that did mark a third loss in four games for Carrick's men in all competitions.
The hosts have let their attacking prowess do the talking in the 2023-24 EFL Cup so far, though, overcoming Huddersfield Town, Exeter City, Bolton Wanderers, Bradford City and most recently Port Vale to reach the final four, scoring at least two goals in each of those victories, all of which have come away from home.
Middlesbrough have managed to progress from each of their last three EFL Cup semi-final ties - most recently triumphing in the 2003-04 edition after stunning Arsenal in the last four that year - but four of their last five home games in the tournament have seen Boro end up on the wrong end of the scoreline.
Chelsea's Midas touch in the final third also briefly eluded them during the visit of Preston to Stamford Bridge on Saturday night, where Mauricio Pochettino's men could not find the key to unlock Ryan Lowe's sturdy backline, but the floodgates opened and then some in the second 45.
Armando Broja delicately guided a deft header into the bottom corner to begin the second-half rout, which also saw Thiago Silva head home at the near post, Raheem Sterling fire in a crisp free kick and Enzo Fernandez wrap up a fantastic four-goal win by tapping home from close range.
As the Blues wait to learn the fate of their fourth-round opponents - which will be confirmed on Monday - preparations will ramp up for a fourth EFL Cup final in the space of seven years; Chelsea progressed from such ties in the 2021-22 and 2018-19 campaigns after falling to Arsenal in the 2017-18 edition.
While Middlesbrough have only taken to the road in this season's EFL Cup, all four of Chelsea's victories against AFC Wimbledon, Blackburn Rovers, Brighton & Hove Albion and Newcastle have come in front of the Stamford Bridge faithful, and they have been defeated in five of their last eight away matches in the competition.
However, a 2-0 win over Middlesbrough in the 2021-22 FA Cup stretched Chelsea's winning streak over their upcoming hosts to nine matches, and they also prevailed by the same scoreline against Boro in the final of the 1997-98 EFL Cup; a repeat on Tuesday would set the Blues well on their way to a showpiece showdown with either Fulham or Liverpool.
Middlesbrough EFL Cup form:
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Middlesbrough form (all competitions):
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Chelsea EFL Cup form:
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Chelsea form (all competitions):
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Team News
While single yellow cards are wiped after completion of the quarter-finals, Middlesbrough attacker Morgan Rogers picked up his second booking of the EFL Cup in the beating of Port Vale, meaning that he must serve a one-game suspension for Tuesday's first leg.
Carrick's reserves will also be depleted by the absences of cup-tied pair Finn Azaz and Sam Greenwood, who represented Plymouth Argyle and Leeds United earlier in the tournament, while Australian duo Samuel Silvera and Riley McGree are away on international duty alongside Senegal goalkeeper Seny Dieng.
No fresh injury concerns reared their ugly heads over the weekend, but all of Tom Smith (Achilles), Darragh Lenihan (Achilles), Lewis O'Brien (ankle), Marcus Forss (thigh) and Patrick McNair (back) remain out of contention for the time being.
Chelsea boss Pochettino is working around his own perpetual absentee crisis once more - a dilemma complicated by Nicolas Jackson's AFCON call-up and a new hip injury for Christopher Nkunku, who was unable to make the squad for the beating of Preston at the weekend.
There is still an outside chance that Nkunku could be passed fit for the first leg - Ben Chilwell (hamstring), Carney Chukwuemeka (knee) and Benoit Badiashile (unspecified) are in the same boat - but Reece James (hamstring), Wesley Fofana (knee), Marc Cucurella (ankle), Robert Sanchez (knee), Lesley Ugochukwu (hamstring), Trevoh Chalobah (thigh) and Romeo Lavia (thigh) are definitely out.
The recently-recalled Andrey Santos is also ineligible on account of representing Nottingham Forest in the EFL Cup during his loan spell, while Ian Maatsen's participation is also clouded in uncertainty amid reports that he has verbally agreed a loan move to Borussia Dortmund.
Middlesbrough possible starting lineup:
Glover; Van den Berg, Clarke, Fry, Bangura; Howson, Barlaser; Jones, Crooks, Latte Lath; Coburn
Chelsea possible starting lineup:
Petrovic; Gusto, Disasi, Silva, Colwill; Gallagher, Fernandez; Madueke, Palmer, Sterling; Broja
We say: Middlesbrough 0-2 Chelsea
Middlesbrough's efforts against title-chasing Aston Villa must be commended, but weary legs and fresh absentees will seriously harm the hosts' chances of a positive first-leg result against a Chelsea side who now come good in the final third more often than not under Pochettino.