Il Nuovo Postiglione - Middlesbrough stun Chelsea flops to take League Cup semi-final lead

Hayden Hackney scored the only goal on 38 minutes as the Championship side held out against Mauricio Pochettino's expensively assembled array of underperforming stars.

A fifth defeat in six away games heaps more pressure on Pochettino, with Chelsea languishing in 10th in the Premier League.

The Blues must turn the tie around when the sides meet again at Stamford Bridge on January 23 to avoid the latest embarrassment in a disappointing first season in charge for the Argentine.

Boro boss Michael Carrick could have been forgiven for cursing his luck after losing top scorer Emmanuel Latte Lath to injury after just three minutes.

Carrick was also forced to withdraw Alex Bangura inside 20 minutes but the second tier side were not fazed as they enjoyed the better of the first 45 minutes.

Middlesbrough had not scored against Chelsea for over 17 years as the Blues had won the past nine meetings between the sides by an aggregate score of 21-0.

However, it was the home side who broke the deadlock eight minutes before half-time.

The pace of Isaiah Jones down the right caused Chelsea's makeshift left-back Levi Colwill problems all night and his low cross was turned in by Hackney from close range.

Chelsea, though, should have at least been level at the break had Cole Palmer maintained his fine scoring form in front of goal.

The former Manchester City academy graduate has been one of Chelsea's few big money signings to hit the ground running under Pochettino.

However, Palmer twice failed to hit the target with glorious first-half chances.

Firstly, he pulled his shot wide from the edge of the area after pouncing on an errant pass from Jonny Howson, and then he fired over the rebound after Tom Glover could only parry Enzo Fernandez's effort.

The flow of the second half was a different story as Chelsea pegged the home side back in search of an equaliser.

But there was a familiarity to the visitors' inability to find a way through.

Despite the club spending over £1 billion ($1.3 billion) on players in the last three transfer windows, Pochettino suggested last month he would need to look to strengthen once more in order to address the lack of a goal threat.

Noni Madueke looked the most likely spark to Chelsea's attack, but he was sacrificed as Pochettino threw on Mykhailo Mudryk and Armando Broja.

Raheem Sterling should have been more alive to meet one dangerous low cross from Broja, but that was all Chelsea's over 80 percent of possession in the final 20 minutes amounted to.

Middlesbrough conceded late to lose 1-0 to Aston Villa in the FA Cup third round on Saturday.

But this time the side that sit 12th in the Championship held out to keep their dreams of a Wembley final against either Liverpool or Fulham very much alive heading into the second leg.

O.Nardolillo--INP