The west Londoners had 72% control and 18 shots on goal to Boro’s six, but were undone by a clever move shortly before half-time that saw hometown lad Hayden Hackney shoot the hosts ahead.
Cole Palmer missed a hat-trick of golden opportunities in the first half, but Chelsea generated significantly less chances in the second half as Middlesbrough dug in and defended admirably.
Chelsea’s season has been marred by a lack of clinicalness in front of goal, and Pochettino was upset that his team was unable to translate their possession into goals, but he was largely satisfied with the performance and optimistic of turning the tie around at Stamford Bridge in two weeks.
‘I think today’s approach was good, we can’t say anything about the mindset,’ the Argentine said afterwards to Sky Sports.
‘Only that we made some errors in the first half, I think we gave them chances to score, and then, yes, they were so aggressive and extremely tough.
‘They played in transition, on the counter-attack, and with an extremely deep block. We had a terrible time breaking down this block.
We had numerous chances to score but failed to do so; that is football, after all. Really unhappy, but it is only the first half of the tie because we have another 90 minutes at Stamford Bridge following this. ‘I believe we need to be optimistic.’
When asked what he attributes Chelsea’s wastefulness this season, Pochettino replied, ‘I think it’s how we compete. We committed several blunders and were punished as a result. In football, something occurs.
‘All that remains is to be tough and to keep pushing. But disappointed since, in my opinion, we were the better side in terms of performance, as we generated more chances and clean chances.
‘But we didn’t score and we weren’t clinical – and that has occurred a lot this season, after six months, I think. We lost so many games because we were not clinical enough.
‘Sometimes we lack the [killer instinct] to score. It’s not that we’re not creating opportunities; we’re creating far too many, but we’re not scoring them, and in this type of game, failing to score makes it impossible to win.’
At full-time, Chelsea’s travelling fans booed the players, prompting Thiago Silva to go over to the away end to attempt to calm them down, and Pochettino believes they were within their rights to be disappointed.
When asked about the incident at full-time, he said, ‘I did not see, I did not see what was going on there. I can’t say much about it except that we appreciate that our fans are frustrated, but there are still 90 minutes to go.’