Mauricio Pochettino believes that Chelsea’s biggest problem this season is that they are not clinical enough.

The Blues were beaten 1-0 by Middlesbrough when the two sides faced off in the Carabao Cup semis on Tuesday night.

Chelsea had 72% of the ball, and created a few good chances at the Riverside, but they just couldn’t convert any of them.

The defeat means Chelsea will now have to win by two goals in the return leg at Stamford Bridge in two weeks time to secure a place in the final vs either Liverpool or Fulham.

Asked why Chelsea have been poor at converting their chances this season, Pochettino said in a post-match interview: “I think it’s how we compete. We made some mistakes and we were punished for that. In football that happens.

“There’s only to be tough and to keep pushing. But disappointed because I think if we assess the performance we were the better side, we created more chances, we create clear chances.

“But we didn’t score and we were not clinical – and that has happened during this season, after six months I think it has happened a lot. So many games that we didn’t win because we were not clinical enough.

“We have a lack sometimes of [killer instinct] to score. It’s not that we’re not creating chances, we are creating too many chances, but we are not scoring them and in this type of game if you are not scoring it’s difficult to win.”